ORCID Profile
0000-0002-3877-9772
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Biochemistry and Cell Biology | Protein Targeting And Signal Transduction | Cellular Immunology | Signal Transduction | Oncology and Carcinogenesis | Cancer Cell Biology | Proteomics and Intermolecular Interactions (excl. Medical Proteomics) | Cellular Immunology | Cell Development (Incl. Cell Division And Apoptosis) | Cellular Interactions (incl. Adhesion, Matrix, Cell Wall) | Protein Trafficking | Cell Development, Proliferation and Death | Nanotechnology | Physiology | Synchrotrons; Accelerators; Instruments and Techniques | Basic Pharmacology | Receptors and Membrane Biology | Structural Biology (incl. Macromolecular Modelling) | Microbiology not elsewhere classified | Epigenetics (incl. Genome Methylation and Epigenomics) | Animal Physiology - Systems | Central Nervous System | Peripheral Nervous System | Cellular Interactions (Incl. Adhesion, Matrix, Cell Wall) | Virology | Medicinal and Biomolecular Chemistry not elsewhere classified | Biotechnology Not Elsewhere Classified | Solid Tumours | Haematological Tumours | Molecular Targets | Cancer Genetics | Infectious Agents | Virology | Systems Physiology | Transplantation Immunology | Immunology | Neurosciences | Analytical Biochemistry | Cell Metabolism |
ANZSRC Socio-Economic Objective (SEO)
Biological sciences | Expanding Knowledge in the Biological Sciences | Cancer and Related Disorders | Prevention—biologicals (e.g. vaccines) | Immune System and Allergy | Diagnostics | Infectious Diseases | Immune system and allergy | Nervous System and Disorders | Neurodegenerative Disorders Related to Ageing | Chemical sciences | Physical sciences | Cardiovascular System and Diseases | Diabetes | Child Health | Hearing, vision, speech and their disorders | Blood Disorders | Women's Health | Men's Health | Preventive Medicine | Infectious diseases | Nervous system and disorders | Expanding Knowledge in the Medical and Health Sciences | Behavioural and cognitive sciences | Expanding Knowledge in the Physical Sciences | Other
Related Links
Publications
Comparison of functional properties of thymic and splenic dendritic cells
Publisher: Elsevier BV
Date: 10-1986
DOI: 10.1016/0008-8749(86)90334-5
Abstract: Murine dendritic cells (DC) which are negative for surface immunoglobulin (sIg), Fc receptor (FcR), Thy-1 antigen, and the mononuclear phagocyte-specific marker F4/80, but positive for the DC-specific marker 33D1 and major histocompatibility complex (MHC) Class 1 and Class II antigens were obtained from either the spleen (SDC) or thymus (TDC) and used to stimulate alloreactive cytotoxic T lymphocyte (Tc) generation in vitro, in 5-day mixed lymphocyte reaction (MLR) to investigate some of their functional properties. SDC were potent stimulators of Tc cells in the absence of supernatant of concanavalin-A-stimulated spleen cells (CSS) and using medium containing 1% thioglycolate-stimulated mouse serum (TMS) to avoid potential artifactual helper T cell activation by fetal calf serum (FCS) antigens. TDC did not stimulate Tc cells under these conditions, but did so when mixed with small numbers of SDC, or in the presence of CSS. 33D1 and complement (C')-treated SDC and TDC populations failed to stimulate Tc cell responses in the absence of CSS. In the presence of CSS, TDC treated in a similar manner did not stimulate Tc cell activity, while 33D1 and C'-treated SDC stimulated a weak but detectable Tc cell response. These results indicate that genuine DC were the dominant cells presenting Class I MHC antigens in the TDC population and also that a minority of contaminating non-DC in the SDC population expressed sufficient MHC Class I antigens for Tc cell activation, but did not produce factor(s) required for Tc cell activation. The pretreatment of SDC and TDC with CSS before using them as stimulators did not improve their ability to stimulate Tc cell responses, indicating that the effect of CSS in improving the ability of TDC to stimulate Tc cell responses was not solely due to MHC-elevating effects of components of CSS. Lipopolysaccharide (LPS)-treated SDC synthesized abundant interleukin 1 (IL-1), but TDC synthesized low levels of IL-1. Contact for 24 hr between TDC and splenic Tc cell precursors in medium containing 1% TMS but without CSS and FCS did not tolerize the T cells.
1H magnetic resonance spectroscopy of primary human and murine cells of the myeloid lineage
Publisher: Elsevier BV
Date: 04-1994
Abstract: Murine and human cells of the myeloid lineage can exhibit proton spectra arising primarily from neutral lipid such as triglyceride, similar to other activated and transformed cell types. These spectral characteristics are independent of proliferation or proliferative ability and can be induced in vivo and in vitro in murine peritoneal macrophages by Listeria and interferon-gamma stimulation, respectively. In human peripheral monocytes, this spectrum can develop in the apparent absence of external activating stimuli such as interferon or endotoxin and also occurs in the absence of proliferation. Furthermore, 16-h culture of mixed peripheral blood cells causes concomitant and similar spectral changes in lymphocytes, which do not occur in pure lymphocyte cultures. The lipid spectra induced in mixed cultures develop to the same extent regardless of cell density or the ability to adhere or form aggregates and regardless of whether serum supplementation is of fetal bovine or adult human origin. Unlike peritoneal macrophages, the addition of interferon-gamma causes no additional spectral changes in adherent or nonadherent cultures. However, reduction of serum concentrations in culture medium causes a dose-dependent decrease in the acquired lipid signal. The observed spectral differences between human and murine myeloid populations could be species-dependent but could also be due to their differentiation status.
Integrated immune dynamics define correlates of COVID-19 severity and antibody responses
Publisher: Elsevier BV
Date: 03-2021
Immune Modulation of Monocytes Dampens the IL-17+ γδ T Cell Response and Associated Psoriasis Pathology in Mice
Publisher: Elsevier BV
Date: 12-2020
Comparative proteomics in the corpus callosal sub-regions of postmortem human brain
Publisher: Elsevier BV
Date: 12-2009
DOI: 10.1016/J.NEUINT.2009.04.017
Abstract: The corpus callosum (CC) is a single anatomical region with homologous cytoarchitecture and ided into four sub-regions such as the rostrum, the genu, the body and the splenium. Neuroimaging analysis revealed that susceptibility to clinical neurological diseases of these sub-regions is variable, indicating biochemical and physiological heterogenecity. To understand the biochemical make up of these regions, we compared the protein expression of these three sub-regional areas [the genu, the body and the splenium (n=9)] through 2D proteomics, which is a high-throughput global protein expression analysis technique. Normative proteomic comparison of gels, and analysis of spectra revealed that 17 (identified as 7 proteins), 35 (identified as 20 proteins) and 39 (identified as 21 proteins) protein spots were differentially expressed in the genu vs. the body, the genu vs. the splenium and the body vs. the splenium, respectively. These results suggest that the sub-regions of the CC differ at the level of protein expression. Identified proteins of the different groups belong to several functional classes such as cytoskeletal, metabolic, signaling, oxidative stress and calcium regulation. Interestingly, oxidative stress defense and glucose metabolic pathways of the splenium are quite different from the genu which might be correlated to region specific vulnerability of neuronal illness. Protein expression maps of these regions can be used as a reference source for future studies to investigate the molecular basis of functional differences and degree of pathogenesis of various neurodegenerative diseases of the CC.
IFN regulatory factor 8 is a key constitutive determinant of the morphological and molecular properties of microglia in the CNS.
Publisher: Public Library of Science (PLoS)
Date: 14-11-2012
COmputer-assisted learning: Evaluation of a medical diagnostic reasoning program
Publisher: Informa UK Limited
Date: 1997
Human retinoblastoma: In vitro differentiation and immunoglobulin superfamily antigen modulation by retinoic acid
Publisher: Springer Science and Business Media LLC
Date: 18-06-1997
Abstract: Suspension and attachment cultures of Y79 human retinoblastoma cells were treated with all-trans retinoic acid (RA) for up to 10 days to assess its effect on growth and cell-surface expression of immunoglobulin superfamily antigens MHC class I and class II, ICAM-1, NCAM and Thy1. RA up to 10 microM induced growth inhibition, and marked morphological differentiation with extension of prominent processes resembling neurites was seen in attachment cultures. However, above 10 microM RA produced extensive cell death. We also observed increased cell-surface expression of MHC class I, ICAM-1, NCAM and Thy1 on Y79 cells treated with 10 microM over 10 days constitutive MHC class II expression was not apparent, nor did RA treatment appear to induce Y79 cells to express MHC class immunoreactivity. The up-modulation of cell-adhesion molecules (NCAM, ICAM-1 and Thy1) and immune recognition molecules (NCAM, ICAM-1 and MHC class I), associated with reduced growth and tumour cell differentiation, suggests that RA may have a potential role in regulating the growth and development of retinoblastoma tumours.
Enhanced Antigen Processing or Immune Evasion? West Nile Virus and the Induction of Immune Recognition Molecules
Publisher: Springer New York
Date: 2009
Evaluation of a Diagnostic Reasoning Program (DxR): Exploring Student Perceptions and Addressing Faculty Concerns
Publisher: Ubiquity Press, Ltd.
Date: 12-05-1998
DOI: 10.5334/1998-1
Relationship between surface H-2 concentration, size of different target cells, and lysis by cytotoxic T cells
Publisher: Elsevier BV
Date: 04-1986
DOI: 10.1016/0008-8749(86)90311-4
Abstract: We have examined the parameters of target cell cross-sectional area and surface H-2 concentration in relation to their susceptibility to cytotoxic T-cell-mediated lysis, using a series of commonly used murine target cells of the H-2k haplotype. We used a sensitive immunoferritin labeling technique and electron microscopy to estimate relative cell diameter and H-2 concentration combined with standard 51Cr-release assays for cytotoxicity. We found that susceptibility to cytotoxic T-cell lysis was not related consistently to either factor alone, but was related to a combination of the two, such that above a certain value for the product of the two factors, no further increase in cytotoxic T-cell efficiency was seen. The information presented here should be of value to workers seeking to select a target cell type that will maximize the sensitivity of 51Cr-release-based assays for the detection of cytotoxic T cells.
Generalized minimax inequalities for set-valued mappings
Publisher: Elsevier BV
Date: 05-2003
An extreme particle accelerator in the Galactic plane: HESS J1826−130
Publisher: EDP Sciences
Date: 12-2020
DOI: 10.1051/0004-6361/202038851
Abstract: The unidentified very-high-energy (VHE E 0.1 TeV) γ -ray source, HESS J1826−130, was discovered with the High Energy Stereoscopic System (HESS) in the Galactic plane. The analysis of 215 h of HESS data has revealed a steady γ -ray flux from HESS J1826−130, which appears extended with a half-width of 0.21° ± 0.02 stat ° ± 0.05 sys °. The source spectrum is best fit with either a power-law function with a spectral index Γ = 1.78 ± 0.10 stat ± 0.20 sys and an exponential cut-off at 15.2 −3.2 +5.5 TeV, or a broken power-law with Γ 1 = 1.96 ± 0.06 stat ± 0.20 sys , Γ 2 = 3.59 ± 0.69 stat ± 0.20 sys for energies below and above E br = 11.2 ± 2.7 TeV, respectively. The VHE flux from HESS J1826−130 is contaminated by the extended emission of the bright, nearby pulsar wind nebula, HESS J1825−137, particularly at the low end of the energy spectrum. Leptonic scenarios for the origin of HESS J1826−130 VHE emission related to PSR J1826−1256 are confronted by our spectral and morphological analysis. In a hadronic framework, taking into account the properties of dense gas regions surrounding HESS J1826−130, the source spectrum would imply an astrophysical object capable of accelerating the parent particle population up to ≳200 TeV. Our results are also discussed in a multiwavelength context, accounting for both the presence of nearby supernova remnants, molecular clouds, and counterparts detected in radio, X-rays, and TeV energies.
Two-Dimensional 1H NMR Studies of Membrane Changes during the Activation of Primary T Lymphocytes
Publisher: Elsevier BV
Date: 04-1994
Abstract: Two-dimensional 1H NMR spectroscopy was used to quantify the level of "mobile" plasma membrane triglyceride and the intracellular concentrations of water-soluble phospholipid precursors during the activation of both mature and immature primary T lymphocytes. The concentration of mobile triglyceride in the plasma membrane was seen to increase approximately 35-fold during 72 h of activation of murine thymic and splenic T lymphocytes with ionomycin and phorbol 12-myristate 13-acetate. This dramatic increase in mobile plasma membrane triglyceride during the activation of both mature and immature T-lymphocyte populations supports the hypothesis that immune cell activation is associated with increased plasma membrane fluidity. The intracellular concentrations of various phospholipid precursors were shown to increase during the early stages of T-lymphocyte activation and then remain at levels above those in resting cells. This may facilitate de novo phospholipid biosynthesis, which is presumably necessary since cell volume, and hence the plasma membrane surface area, was demonstrated to increase significantly during T-lymphocyte activation. Various models that might explain the origin of the NMR-visible plasma membrane triglyceride that is observed during immune cell activation and malignant transformation are examined.
West Nile virus infection induces susceptibility of in vitro outgrown murine blastocysts to specific lysis by paternally directed allo-immune and virus-immune cytotoxic T cells
Publisher: Elsevier BV
Date: 03-1993
DOI: 10.1016/0165-0378(93)90003-Z
Abstract: Day 3 post-coitum BALB/c and (BALB/c x CBA/H)F1 blastocysts were isolated and hatched in replicate wells. Some were treated with interferon-gamma (IFN-gamma). Whilst others were infected with West Nile Virus (WNV) at 100 plaque-forming units per cell, for 18 h. Controls were mock-treated. Gamma-irradiated (2000 rads) CBA/H, (paternal) WNV-specific and allo(CBA/H)-specific cytotoxic T (Tc) cells were then added to replicates of infected, mock-infected or IFN-gamma-treated cultures for 20 h. [3H]Thymidine was then added for a further 8 h. [3H]Thymidine incorporation was inhibited by 40-50% in WNV-infected cultures exposed to WNV-paternal-specific Tc cells and by 30-40% in WNV-infected cultures exposed to allo-paternal-specific Tc cells compared to similarly exposed, uninfected, or unexposed, WNV-infected, or unexposed, uninfected cultures. No significant differences in [3H]thymidine incorporation were found between these controls and IFN-gamma-treated cultures exposed to allo-paternal-specific Tc cells or IFN-gamma-treated cultures not exposed to Tc cells. Parallel exposure of L929 fibroblasts to the same Tc cells irradiated with 500-8000 rads in doubling doses, showed that irradiation did not alter the efficacy or specificity of the Tc cells. Relevance to maternal anti-viral immune responses during implantation is discussed.
Cytosolic Phospholipase A2-α: A Potential Therapeutic Target for Prostate Cancer
Publisher: American Association for Cancer Research (AACR)
Date: 15-12-2008
DOI: 10.1158/1078-0432.CCR-08-0566
Abstract: Purpose: Cytosolic phospholipase A2-α (cPLA2-α) provides intracellular arachidonic acid to supply both cyclooxygenase and lipoxygenase pathways. We aim to determine the expression and activation of cPLA2-α in prostate cancer cell lines and tissue and the effect of targeting cPLA2-α in vitro and in vivo. Experimental Design: The expression of cPLA2-α was determined in prostate cancer cells by reverse transcription-PCR, Western blot, and immunocytochemistry. Growth inhibition, apoptosis, and cPLA2-α activity were determined after inhibition with cPLA2-α small interfering RNA or inhibitor (Wyeth-1). Cytosolic PLA2-α inhibitor or vehicle was also administered to prostate cancer xenograft mouse models. Finally, the expression of phosphorylated cPLA2-α was determined by immunohistochemistry in human normal, androgen-sensitive and androgen-insensitive prostate cancer specimens. Results: cPLA2-α is present in all prostate cancer cells lines, but increased in androgen-insensitive cells. Inhibition with small interfering RNA or Wyeth-1 results in significant reductions in prostate cancer cell numbers, as a result of reduced proliferation as well as increased apoptosis, and this was also associated with a reduction in cPLA2-α activity. Expression of cyclin D1 and phosphorylation of Akt were also observed to decrease. Wyeth-1 inhibited PC3 xenograft growth by ∼33% and again, also reduced cyclin D1. Immunohistochemistry of human prostate tissue revealed that phosphorylated cPLA2-α is increased when hormone refractory is reached. Conclusions: Expression and activation of cPLA2-α are increased in the androgen-insensitive cancer cell line and tissue. Inhibition of cPLA2-α results in cells and xenograft tumor growth inhibition and serves as a potentially effective therapy for hormone refractory prostate cancer.
The bacteriostatic protein lipocalin 2 is induced in the central nervous system of mice with west nile virus encephalitis
Publisher: American Society for Microbiology
Date: 2014
DOI: 10.1128/JVI.02094-13
Abstract: Lipocalin 2 (Lcn2) is a bacteriostatic factor produced during the innate immune response to bacterial infection. Whether Lcn2 has a function in viral infection is unknown. We investigated the regulation and function of Lcn2 in the central nervous system (CNS) of mice during West Nile virus (WNV) encephalitis. Lcn2 mRNA and protein were induced in the brain by day 5, and this induction increased further by day 7 postinfection but was delayed compared with the induction of the toll-like receptor 3 (TLR3) gene, retinoic acid-inducible gene 1 (RIG-I), and melanoma differentiation-associated protein 5 (MDA5) gene. The Lcn2 mRNA and protein were both found at high levels in the choroid plexus, vascular endothelium, macrophage/microglia, and astrocytes. However, some neuronal subsets contained Lcn2 protein but no detectable mRNA. In Lcn2 knockout (KO) mice, with the exception of CXC motif chemokine 5 (CXCL5), which was significantly more downregulated than in wild-type (WT) mice, expression levels of a number of other host response genes were similar in the two genotypes. The brain from Lcn2 and WT mice with WNV encephalitis contained similar numbers of infiltrating macrophages, granulocytes, and T cells. Lcn2 KO and WT mice had no significant difference in tissue viral loads or survival after infection with different doses of WNV. We conclude that Lcn2 gene expression is induced to high levels in a time-dependent fashion in a variety of cells and regions of the CNS of mice with WNV encephalitis. The function of Lcn2 in the host response to WNV infection remains largely unknown, but our data indicate that it is dispensable as an antiviral or immunoregulatory factor in WNV encephalitis.
A theoretical model of the West Nile Virus survival data
Publisher: Springer Science and Business Media LLC
Date: 06-2017
Dietary protein increases T-cell-independent sIgA production through changes in gut microbiota-derived extracellular vesicles
Publisher: Springer Science and Business Media LLC
Date: 27-07-2022
DOI: 10.1038/S41467-022-31761-Y
Abstract: Secretory IgA is a key mucosal component ensuring host-microbiota mutualism. Here we use nutritional geometry modelling in mice fed 10 different macronutrient-defined, isocaloric diets, and identify dietary protein as the major driver of secretory IgA production. Protein-driven secretory IgA induction is not mediated by T-cell-dependent pathways or changes in gut microbiota composition. Instead, the microbiota of high protein fed mice produces significantly higher quantities of extracellular vesicles, compared to those of mice fed high-carbohydrate or high-fat diets. These extracellular vesicles activate Toll-like receptor 4 to increase the epithelial expression of IgA-inducing cytokine, APRIL, B cell chemokine, CCL28, and the IgA transporter, PIGR. We show that succinate, produced in high concentrations by microbiota of high protein fed animals, increases generation of reactive oxygen species by bacteria, which in turn promotes extracellular vesicles production. Here we establish a link between dietary macronutrient composition, gut microbial extracellular vesicles release and host secretory IgA response.
Immune responses in COVID-19 respiratory tract and blood reveal mechanisms of disease severity
Publisher: Research Square Platform LLC
Date: 26-08-2021
DOI: 10.21203/RS.3.RS-802084/V1
Abstract: Although the respiratory tract is the primary site of SARS-CoV-2 infection and the ensuing immunopathology, respiratory immune responses are understudied and urgently needed to understand mechanisms underlying COVID-19 disease pathogenesis. We collected paired longitudinal blood and respiratory tract s les (endotracheal aspirate, sputum or pleural fluid) from hospitalized COVID-19 patients and non-COVID-19 controls. Cellular, humoral and cytokine responses were analysed and correlated with clinical data. SARS-CoV-2-specific IgM, IgG and IgA antibodies were detected using ELISA and multiplex assay in both the respiratory tract and blood of COVID-19 patients, although a higher receptor binding domain (RBD)-specific IgM and IgG seroconversion level was found in respiratory specimens. SARS-CoV-2 neutralization activity in respiratory s les was detected only when high levels of RBD-specific antibodies were present. Strikingly, cytokine/chemokine levels and profiles greatly differed between respiratory s les and plasma, indicating that inflammation needs to be assessed in respiratory specimens for the accurate assessment of SARS-CoV-2 immunopathology. Diverse immune cell subsets were detected in respiratory s les, albeit dominated by neutrophils. Importantly, we also showed that dexamethasone and/or remdesivir treatment did not affect humoral responses in blood of COVID-19 patients. Overall, our study unveils stark differences in innate and adaptive immune responses between respiratory s les and blood and provides important insights into effect of drug therapy on immune responses in COVID-19 patients.
Antibody penetration of viable human cells. II. Anti-RNP antibodies binding to RNP antigen expressed on cell surface, which may mediate the antibody internalization.
Publisher: Oxford University Press (OUP)
Date: 09-1993
DOI: 10.1111/J.1365-2249.1993.TB08191.X
Abstract: As U1 small nuclear ribonucleoprotein (U1 snRNP2) has a crucial role in pre-mRNP splicing, the interaction of anti-RNP antibody with snRNP within viable lymphocytes may profoundly influence cell functions. We have shown that antibody can penetrate viable human lymphocytes, and anti-RNP antibodies enter more cells than other anti-nuclear antibodies or control IgG. In order to study the in vitro interaction of anti-RNP antibodies with viable cells. T lymphocytes were metabolically labelled with 35S-methionine, then incubated with the antibodies and washed. A set of 35S-labelled cell-associated snRNP polypeptides A, B′/B, C and D were found to bind to both monospecific human polyclonal anti-RNP IgG (human anti-RNP IgG) and a mouse monoclonal anti-RNP antibody (2·73), indicating that anti-RNP antibodies interacted with RNP antigen inside or/and on the surface of viable cells. To investigate antibody binding to RNP antigen on the cell surface, the cell surface proteins were either iodinated with 125I or the cells processed for immunoelectron microscopic studices after incubation with MoAb. At least seven 125I-labelled polypeptides on the cell surface were found to be immunoprecipitated by the anti-RNP MoAb which have similar molecular weights to U snRNP polypeptidcs 70K, A, B, D, E, F, and G. The immunoelectron microscopic studies showed that the gold particles formed clustered patches on the cell membrane. Further studies suggested that RNP antigen bound to the cell surface, and the RNP binding structure was probably a heterodimer receptor. This study provides evidence to suggest that anti-RNP antibody entry into viable cells may be mediated by interaction with RNP antigen expressed on the cell surface.
Dysbiosis in imiquimod-induced psoriasis alters gut immunity and exacerbates colitis development
Publisher: Elsevier BV
Date: 08-2022
DOI: 10.1016/J.CELREP.2022.111191
Abstract: Psoriasis has long been associated with inflammatory bowel disease (IBD) however, a causal link is yet to be established. Here, we demonstrate that imiquimod-induced psoriasis (IMQ-pso) in mice disrupts gut homeostasis, characterized by increased proportions of colonic CX
Using single-cell cytometry to illustrate integrated multi-perspective evaluation of clustering algorithms using Pareto fronts.
Publisher: Oxford University Press (OUP)
Date: 28-01-2021
DOI: 10.1093/BIOINFORMATICS/BTAB038
Abstract: Many ‘automated gating’ algorithms now exist to cluster cytometry and single-cell sequencing data into discrete populations. Comparative algorithm evaluations on benchmark datasets rely either on a single performance metric, or a few metrics considered independently of one another. However, single metrics emphasize different aspects of clustering performance and do not rank clustering solutions in the same order. This underlies the lack of consensus between comparative studies regarding optimal clustering algorithms and undermines the translatability of results onto other non-benchmark datasets. We propose the Pareto fronts framework as an integrative evaluation protocol, wherein in idual metrics are instead leveraged as complementary perspectives. Judged superior are algorithms that provide the best trade-off between the multiple metrics considered simultaneously. This yields a more comprehensive and complete view of clustering performance. Moreover, by broadly and systematically s ling algorithm parameter values using the Latin Hypercube s ling method, our evaluation protocol minimizes (un)fortunate parameter value selections as confounding factors. Furthermore, it reveals how meticulously each algorithm must be tuned in order to obtain good results, vital knowledge for users with novel data. We exemplify the protocol by conducting a comparative study between three clustering algorithms (ChronoClust, FlowSOM and Phenograph) using four common performance metrics applied across four cytometry benchmark datasets. To our knowledge, this is the first time Pareto fronts have been used to evaluate the performance of clustering algorithms in any application domain. Implementation of our Pareto front methodology and all scripts and datasets to reproduce this article are available at har1821/ParetoBench. Supplementary data are available at Bioinformatics online.
Temporal tracking of microglial and monocyte single-cell transcriptomics in lethal flavivirus infection
Publisher: Springer Science and Business Media LLC
Date: 04-04-2023
DOI: 10.1186/S40478-023-01547-4
Abstract: As the resident parenchymal myeloid population in the central nervous system (CNS), microglia are strategically positioned to respond to neurotropic virus invasion and have been implicated in promoting both disease resolution and progression in the acute and post-infectious phase of virus encephalitis. In a mouse model of West Nile virus encephalitis (WNE), infection of the CNS results in recruitment of large numbers of peripheral immune cells into the brain, the majority being nitric oxide (NO)-producing Ly6C hi inflammatory monocyte-derived cells (MCs). In this model, these cells enhance immunopathology and mortality. However, the contribution of microglia to this response is currently undefined. Here we used a combination of experimental tools, including single-cell RNA sequencing (scRNA-seq), microglia and MC depletion reagents, high-dimensional spectral cytometry and computational algorithms to dissect the differential contribution of microglia and MCs to the anti-viral immune response in severe neuroinflammation seen in WNE. Intriguingly, analysis of scRNA-seq data revealed 6 unique microglia and 3 unique MC clusters that were predominantly timepoint-specific, demonstrating substantial transcriptional adaptation with disease progression over the course of WNE. While microglia and MC adopted unique gene expression profiles, gene ontology enrichment analysis, coupled with microglia and MC depletion studies, demonstrated a role for both of these cells in the trafficking of peripheral immune cells into the CNS, T cell responses and viral clearance. Over the course of infection, microglia transitioned from a homeostatic to an anti-viral and then into an immune cell-recruiting phenotype. Conversely, MC adopted antigen-presenting , immune cell-recruiting and NO-producing phenotypes, which all had anti-viral function. Overall, this study defines for the first time the single-cell transcriptomic responses of microglia and MCs over the course of WNE, demonstrating both protective and pathological roles of these cells that could potentially be targeted for differential therapeutic intervention to d en immune-mediated pathology, while maintaining viral clearance functions.
Constraints on the Intergalactic Magnetic Field Using Fermi-LAT and H.E.S.S. Blazar Observations
Publisher: American Astronomical Society
Date: 06-2023
Abstract: Magnetic fields in galaxies and galaxy clusters are believed to be the result of the lification of intergalactic seed fields during the formation of large-scale structures in the universe. However, the origin, strength, and morphology of this intergalactic magnetic field (IGMF) remain unknown. Lower limits on (or indirect detection of) the IGMF can be obtained from observations of high-energy gamma rays from distant blazars. Gamma rays interact with the extragalactic background light to produce electron−positron pairs, which can subsequently initiate electromagnetic cascades. The gamma-ray signature of the cascade depends on the IGMF since it deflects the pairs. Here we report on a new search for this cascade emission using a combined data set from the Fermi Large Area Telescope and the High Energy Stereoscopic System. Using state-of-the-art Monte Carlo predictions for the cascade signal, our results place a lower limit on the IGMF of B 7.1 × 10 −16 G for a coherence length of 1 Mpc even when blazar duty cycles as short as 10 yr are assumed. This improves on previous lower limits by a factor of 2. For longer duty cycles of 10 4 (10 7 ) yr, IGMF strengths below 1.8 × 10 −14 G (3.9 × 10 −14 G) are excluded, which rules out specific models for IGMF generation in the early universe.
Targeted blockade in lethal West Nile virus encephalitis indicates a crucial role for very late antigen (VLA)-4-dependent recruitment of nitric oxide-producing macrophages.
Publisher: Springer Science and Business Media LLC
Date: 30-10-2012
Abstract: Infiltration of Ly6C hi monocytes from the blood is a hallmark of viral encephalitis. In mice with lethal encephalitis caused by West Nile virus (WNV), an emerging neurotropic flavivirus, inhibition of Ly6C hi monocyte trafficking into the brain by anti-very late antigen (VLA)-4 integrin antibody blockade at the time of first weight loss and leukocyte influx resulted in long-term survival of up to 60% of infected mice, with subsequent sterilizing immunity. This treatment had no effect on viral titers but appeared to be due to inhibition of Ly6C hi macrophage immigration. Although macrophages isolated from the infected brain induced WNV-specific CD4 + T-cell proliferation, T cells did not directly contribute to pathology, but are likely to be important in viral control, as antibody-mediated T-cell depletion could not reproduce the therapeutic benefit of anti-VLA-4. Instead, 70% of infiltrating inflammatory monocyte-derived macrophages were found to be making nitric oxide (NO). Furthermore, aminoguanidine-mediated inhibition of induced NO synthase activity in infiltrating macrophages significantly prolonged survival, indicating involvement of NO in the immunopathology. These data show for the first time the therapeutic effects of temporally targeting pathogenic NO-producing macrophages during neurotropic viral encephalitis.
Collateral Damage: What Effect Does Anti-CD4 and Anti-CD8α Antibody–Mediated Depletion Have on Leukocyte Populations?
Publisher: The American Association of Immunologists
Date: 10-2018
Abstract: Anti-CD4 or anti-CD8α Ab–mediated depletion strategies are widely used to determine the role of T cell subsets. However, surface expression of CD4 and CD8α is not limited to T cells and occurs on other leukocyte populations as well. Using both unbiased t-distributed stochastic neighbor embedding of flow cytometry data and conventional gating strategies, we assessed the impact of anti-CD4 and anti-CD8α Ab–mediated depletion on non–T cell populations in mice. Our results show that anti-CD4 and anti-CD8α Ab injections not only resulted in depletion of T cells but also led to depletion of specific dendritic cell subsets in a dose-dependent manner. Importantly, the extent of this effect varied between mock- and virus-infected mice. We also demonstrate the importance of using a second, noncompeting Ab (clone CT-CD8α) to detect CD8α+ cells following depletion with anti-CD8α Ab clone 2.43. Our study provides a necessary caution to carefully consider the effects on nontarget cells when using Ab injections for leukocyte depletion in all experimental conditions.
SARS-CoV-2 infection results in immune responses in the respiratory tract and peripheral blood that suggest mechanisms of disease severity
Publisher: Springer Science and Business Media LLC
Date: 19-05-2022
DOI: 10.1038/S41467-022-30088-Y
Abstract: Respiratory tract infection with SARS-CoV-2 results in varying immunopathology underlying COVID-19. We examine cellular, humoral and cytokine responses covering 382 immune components in longitudinal blood and respiratory s les from hospitalized COVID-19 patients. SARS-CoV-2-specific IgM, IgG, IgA are detected in respiratory tract and blood, however, receptor-binding domain (RBD)-specific IgM and IgG seroconversion is enhanced in respiratory specimens. SARS-CoV-2 neutralization activity in respiratory s les correlates with RBD-specific IgM and IgG levels. Cytokines/chemokines vary between respiratory s les and plasma, indicating that inflammation should be assessed in respiratory specimens to understand immunopathology. IFN-α2 and IL-12p70 in endotracheal aspirate and neutralization in sputum negatively correlate with duration of hospital stay. Diverse immune subsets are detected in respiratory s les, dominated by neutrophils. Importantly, dexamethasone treatment does not affect humoral responses in blood of COVID-19 patients. Our study unveils differential immune responses between respiratory s les and blood, and shows how drug therapy affects immune responses during COVID-19.
Microparticles as Immune Regulators in Infectious Disease ? An Opinion
Publisher: Frontiers Media SA
Date: 2011
Site-specific production of IL-6 in the central nervous system retargets and enhances the inflammatory response in experimental autoimmune encephalomyelitis
Publisher: The American Association of Immunologists
Date: 08-2009
Abstract: IL-6 is crucial for the induction of many murine models of autoimmunity including experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis. To establish the role of site-specific production of IL-6 in autoimmunity, we examined myelin oligodendrocyte glycoprotein immunization-induced EAE in transgenic mice (GFAP-IL6) with IL-6 production restricted to the cerebellum. Myelin oligodendrocyte glycoprotein-immunized (Mi-) GFAP-IL6 mice developed severe ataxia but no physical signs of spinal cord involvement, which was in sharp contrast to Mi-wild type (WT) animals that developed classical EAE with ascending paralysis. Immune pathology and demyelination were nearly absent from the spinal cord, but significantly increased in the cerebellum of Mi-GFAP-IL6 mice. Tissue damage in the cerebellum in the Mi-GFAP-IL6 mice was accompanied by increased total numbers of infiltrating leukocytes and increased proportions of both neutrophils and B-cells. With the exception of IL-17 mRNA, which was elevated in both control immunized and Mi-GFAP-IL6 cerebellum, the level of other cytokine and chemokine mRNAs were comparable with Mi-WT cerebellum whereas significantly higher levels of IFN-γ and TNF-α mRNA were found in Mi-WT spinal cord. Thus, site-specific production of IL-6 in the cerebellum redirects trafficking away from the normally preferred antigenic site the spinal cord and acts as a leukocyte “sink” that markedly enhances the inflammatory cell accumulation and disease. The mechanisms underlying this process likely include the induction of specific chemokines, activation of microglia, and activation and loss of integrity of the blood-brain barrier present in the cerebellum of the GFAP-IL6 mice before the induction of EAE.
Multiplex analysis of mass imaging data: Application to the pathology of experimental myocardial infarction
Publisher: Wiley
Date: 02-2022
DOI: 10.1111/APHA.13790
Abstract: Imaging mass cytometry (IMC) affords simultaneous immune‐labelling/imaging of multiple antigens in the same tissue. Methods utilizing multiplex data beyond co‐registration are lacking. This study developed and applied an innovative spatial analysis workflow for multiplex imaging data to IMC data determined from cardiac tissues and revealed the mechanism(s) of neutrophil‐mediated post‐myocardial‐infarction damage. IMC produced multiplex images with various redox/inflammatory markers. The cardiac peri‐infarct zone (PIZ) was determined to be up to 240 µm from the infarct border based on the presence of neutrophils. The tissue region beyond the infarct was defined as the remote area (RA). ImageJ was used to quantify the immunoreactivity. Functional assessments included infarct size, cell necro/apoptosis, total thiol assay and echocardiogram. Expression of damage markers decreased in order from the infarct area to PIZ and then RA, reflecting the neutrophil density in the regions. Concentrically spaced “shoreline contour analysis” around the cardiac infarct extending into the PIZ showed that immunoreactivity for damage markers decreased linearly with increasing distance from the infarct, concomitant with a decreasing neutrophil‐myeloperoxidase (MPO) gradient from the infarct to the PIZ. Stratifying by concentric bands around in idual MPO + ‐signal identified that the immunoreactivity of haem‐oxygenase‐1 (HO‐1) and phosphorylated‐p38 mitogen‐activated protein kinase (pP38) peaked near neutrophils. Furthermore, spatial dependence between neutrophils and markers of cardiac cellular damage was confirmed by nearest‐neighbour distance analysis. Post‐infarction tissue exhibited declined functional parameters that were associated with neutrophil migration from the infarct to PIZ. This image‐based quantitative protocol revealed the spatial association and provided potential molecular pathways responsible for neutrophil‐mediated damage post‐infarction.
Immunopathology of flavivirus infections
Publisher: Wiley
Date: 05-12-2007
Abstract: With the recent emergence of the flavivirus, West Nile virus (WNV), in particular, the New York strain of Lineage I WNV in North America in 1999, there has been a significant increase in activity in neurotropic flavivirus research. These viruses cause encephalitis that can result in permanent neurological sequelae or death. Attempts to develop vaccines have made progress, but have been variably successful, despite considerable commercial underwriting. Thus, the discovery of ways and means to combat disease is no less urgent. As such, most recent work has been directed towards dissecting and understanding the pathogenesis of disease, as a way of informing possible approaches to abrogation or amelioration of illness. Whether inherent to flaviviruses or because humans are incidental, dead-end hosts, it is clear that these viruses interact with their human hosts in extremely complex ways. This occurs from the cellular level, at which infection must be established to produce disease, to its interaction with the adaptive immune response, which may result in its eradication, with or without immunopathological and consequent neurological sequelae. As human proximity to and contact with flavivirus insect vectors and lifying hosts cannot practically be eliminated, our understanding of the pathogenesis of flavivirus-induced diseases, especially with regard to possible targets for treatment, is imperative.
Time-resolved hadronic particle acceleration in the recurrent nova RS Ophiuchi
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-2022
Abstract: Recurrent novae are repeating thermonuclear explosions in the outer layers of white dwarfs, due to the accretion of fresh material from a binary companion. The shock generated when ejected material slams into the companion star’s wind can accelerate particles. We report very-high-energy (VHE ≳ 100 giga–electron volts ) gamma rays from the recurrent nova RS Ophiuchi, up to 1 month after its 2021 outburst, observed using the High Energy Stereoscopic System (H.E.S.S.). The temporal profile of VHE emission is similar to that of lower-energy giga–electron volt emission, indicating a common origin, with a 2-day delay in peak flux. These observations constrain models of time-dependent particle energization, favoring a hadronic emission scenario over the leptonic alternative. Shocks in dense winds provide favorable environments for efficient acceleration of cosmic rays to very high energies.
Immunomodulatory Effects of Bone Marrow-Derived Mesenchymal Stem Cells on Pro-Inflammatory Cytokine-Stimulated Human Corneal Epithelial Cells
Publisher: Public Library of Science (PLoS)
Date: 08-07-2014
Ocular tropism of SARS-CoV-2 in animal models with retinal inflammation via neuronal invasion following intranasal inoculation
Publisher: Springer Science and Business Media LLC
Date: 12-12-2022
DOI: 10.1038/S41467-022-35225-1
Abstract: Although ocular manifestations are reported in patients with COVID-19, consensus on ocular tropism of SARS-CoV-2 is lacking. Here, we infect K18-hACE2 transgenic mice with SARS-CoV-2 using various routes. We observe ocular manifestation and retinal inflammation with production of pro-inflammatory cytokines in the eyes of intranasally (IN)-infected mice. Intratracheal (IT) infection results in dissemination of the virus from the lungs to the brain and eyes via trigeminal and optic nerves. Ocular and neuronal invasions are confirmed using intracerebral (IC) infection. Notably, the eye-dropped (ED) virus does not cause lung infection and becomes undetectable with time. Ocular and neurotropic distribution of the virus in vivo is evident in fluorescence imaging with an infectious clone of SARS-CoV-2-mCherry. The ocular tropic and neuroinvasive characteristics of SARS-CoV-2 are confirmed in wild-type Syrian hamsters. Our data can improve the understanding regarding viral transmission and clinical characteristics of SARS-CoV-2 and help in improving COVID-19 control procedures.
HESS J1809−193: A halo of escaped electrons around a pulsar wind nebula?
Publisher: EDP Sciences
Date: 04-2023
Revealing x-ray and gamma ray temporal and spectral similarities in the GRB 190829A afterglow
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-06-2021
Class I major histocompatibility complex antigen expression on early murine trophoblast and its induction by lymphokines in vitro
Publisher: Elsevier BV
Date: 04-1987
DOI: 10.1016/0165-0378(87)90034-9
Abstract: The expression of paternal class I and class II major histocompatibility complex (MHC) antigens in cultures of murine ectoplacental cone trophoblast was examined using immunogold labelled antibodies and electron microscopy. Class I MHC antigens could be induced on ectoplacental cone derived trophoblast following exposure to concanavalin A stimulated T cell supernatants. Class I MHC antigens were not detected in untreated trophoblast cultures. Class II MHC antigens were never detected on trophoblast whether treated or untreated. This is the first report of the experimental induction of Class I MHC antigens on a population of normally MHC-negative trophoblast cells.
Magnetic resonance studies of murine macrophages. Proliferation is not a prerequisite for acquisition of an 'activated' high resolution spectrum
Publisher: Wiley
Date: 05-08-1991
DOI: 10.1016/0014-5793(91)80024-W
Abstract: Proton magnetic resonance spectroscopy (1H-MRS) was used to investigate the membranes of macrophages activated by gamma-interferon in vitro and by Listeria monocytogenes in vivo. We report the appearance with activation, of a high resolution spectrum indistinguishable from that found in activated T and B cells and embryonic and malignant cell types previously studied. We furthermore show that proliferation is not a prerequisite for the appearance of this activated spectrum. This supports the idea that membrane 'activation' in all cells, irrespective of origin, may be accompanied by similar architectural changes, and suggests that a common pathway exists for the activation of cell membranes of the immune system, possibly important in the acquisition of increased motility. The use of 1H-MRS as a non-invasive tool for analysis of activation is discussed.
Multiwavelength Observations of the Blazar PKS 0735+178 in Spatial and Temporal Coincidence with an Astrophysical Neutrino Candidate IceCube-211208A
Publisher: American Astronomical Society
Date: 23-08-2023
Abstract: We report on multiwavelength target-of-opportunity observations of the blazar PKS 0735+178, located 2.°2 away from the best-fit position of the IceCube neutrino event IceCube-211208A detected on 2021 December 8. The source was in a high-flux state in the optical, ultraviolet, X-ray, and GeV γ -ray bands around the time of the neutrino event, exhibiting daily variability in the soft X-ray flux. The X-ray data from Swift-XRT and NuSTAR characterize the transition between the low-energy and high-energy components of the broadband spectral energy distribution (SED), and the γ -ray data from Fermi-LAT, VERITAS, and H.E.S.S. require a spectral cutoff near 100 GeV. Both the X-ray and γ -ray measurements provide strong constraints on the leptonic and hadronic models. We analytically explore a synchrotron self-Compton model, an external Compton model, and a lepto-hadronic model. Models that are entirely based on internal photon fields face serious difficulties in matching the observed SED. The existence of an external photon field in the source would instead explain the observed γ -ray spectral cutoff in both the leptonic and lepto-hadronic models and allow a proton jet power that marginally agrees with the Eddington limit in the lepto-hadronic model. We show a numerical lepto-hadronic model with external target photons that reproduces the observed SED and is reasonably consistent with the neutrino event despite requiring a high jet power.
Expression of immunoglobulin superfamily cell adhesion molecules on murine embryonic stem cells
Publisher: Oxford University Press (OUP)
Date: 09-1997
DOI: 10.1095/BIOLREPROD57.3.561
Abstract: The expression of cell adhesion molecules of the Ig superfamily (Ig-CAM) were examined on embryonic stem (ES) cells during culture in vitro. ES cells maintained an undifferentiated phenotype when cultured in the presence of leukemia inhibitory factor (LIF) or with fibroblast feeder cells > 90% of cells reacted positively to an antibody (ECMA-7) that marks undifferentiated ES cells. Using flow cytometry, high concentrations of ICAM-1, VCAM-1, and NCAM antigens were detected on undifferentiated ES cells, but their specific receptors, Mac-1, LFA-1, and VLA-4, were not detected. There was also no class I or II major histocompatibility complex (MHC) antigen expression. The ICAM-1 expressed was functional, since anti-ICAM-1 significantly (p < 0.0001) blocked ES cell-lymphocyte binding. Ig-CAM and MHC-1 expression on undifferentiated ES cells was not up-regulated by treatment of cells with interferon-gamma (IFN-gamma), tumor necrosis factor alpha, or flavivirus infection, agents that up-regulate these molecules in other embryonic cell types. Twelve hours after LIF withdrawal, ICAM-1 and NCAM expression decreased significantly, while VCAM-1 was undetectable. However, morphology and ECMA-7 expression remained unchanged. Similar patterns of expression were seen on ES cells maintained on fibroblast feeder cells. This suggests that LIF or other cytokines may maintain the expression of Ig-CAMs on undifferentiated cells. Differentiation was induced by dimethyl sulfoxide treatment for 14 days. Cells changed from a colony-forming to a monolayer morphology, and approximately 60% of the cell population no longer expressed ECMA-7. In these cells, VCAM-1 was undetectable and ICAM-1 and NCAM had declined to low levels. In these differentiated cells, ICAM-1 and MHC-1 were inducible by IFN-gamma. This study suggests that the pattern of expression of the Ig-CAMs in ES cells may have a role in defining the phenotype of differentiated and undifferentiated cells.
LMC N132D: A mature supernova remnant with a power-law gamma-ray spectrum extending beyond 8 TeV
Publisher: EDP Sciences
Date: 28-10-2021
DOI: 10.1051/0004-6361/202141486
Abstract: Context. Supernova remnants (SNRs) are commonly thought to be the dominant sources of Galactic cosmic rays up to the knee of the cosmic-ray spectrum at a few PeV. Imaging Atmospheric Cherenkov Telescopes have revealed young SNRs as very-high-energy (VHE, GeV) gamma-ray sources, but for only a few SNRs the hadronic cosmic-ray origin of their gamma-ray emission is indisputably established. In all these cases, the gamma-ray spectra exhibit a spectral cutoff at energies much below 100 TeV and thus do not reach the PeVatron regime. Aims. The aim of this work was to achieve a firm detection for the oxygen-rich SNR LMC N132D in the VHE gamma-ray domain with an extended set of data, and to clarify the spectral characteristics and the localization of the gamma-ray emission from this exceptionally powerful gamma-ray-emitting SNR. Methods. We analyzed 252 h of High Energy Stereoscopic System (H.E.S.S.) observations towards SNR N132D that were accumulated between December 2004 and March 2016 during a deep survey of the Large Magellanic Cloud, adding 104 h of observations to the previously published data set to ensure a 5 σ detection. To broaden the gamma-ray spectral coverage required for modeling the spectral energy distribution, an analysis of Fermi -LAT Pass 8 data was also included. Results. We unambiguously detect N132D at VHE with a significance of 5.7 σ . We report the results of a detailed analysis of its spectrum and localization based on the extended H.E.S.S. data set. The joint analysis of the extended H.E.S.S and Fermi -LAT data results in a spectral energy distribution in the energy range from 1.7 GeV to 14.8 TeV, which suggests a high luminosity of N132D at GeV and TeV energies. We set a lower limit on a gamma-ray cutoff energy of 8 TeV with a confidence level of 95%. The new gamma-ray spectrum as well as multiwavelength observations of N132D when compared to physical models suggests a hadronic origin of the VHE gamma-ray emission. Conclusions. SNR N132D is a VHE gamma-ray source that shows a spectrum extending to the VHE domain without a spectral cutoff at a few TeV, unlike the younger oxygen-rich SNR Cassiopeia A. The gamma-ray emission is best explained by a dominant hadronic component formed by diffusive shock acceleration. The gamma-ray properties of N132D may be affected by an interaction with a nearby molecular cloud that partially lies inside the 95% confidence region of the source position.
Flaviviruses in motor neuron disease
Publisher: Wiley
Date: 18-03-2005
DOI: 10.1002/MUS.20320
Abstract: Sporadic motor neuron disease (MND) causes a progressive loss of motor neurons. West Nile virus can attack motor neurons, so we examined whether flavivirus infection could be detected in MND cases. Spinal cord sections from 22 MND cases were stained immunohistochemically with a flavivirus-specific antibody. No staining for flavivirus was seen in any case. Sporadic MND does not appear to arise from a recent infection with a flavivirus.
Diet, commensal microbiota‐derived extracellular vesicles, and host immunity
Publisher: Wiley
Date: 17-05-0202
Abstract: The gut microbiota has co‐evolved with its host, and commensal bacteria can influence both the host's immune development and function. Recently, a role has emerged for bacterial extracellular vesicles (BEVs) as potent immune modulators. BEVs are nanosized membrane vesicles produced by all bacteria, possessing the membrane characteristics of the originating bacterium and carrying an internal cargo that may include nucleic acid, proteins, lipids, and metabolites. Thus, BEVs possess multiple avenues for regulating immune processes, and have been implicated in allergic, autoimmune, and metabolic diseases. BEVs are biodistributed locally in the gut, and also systemically, and thus have the potential to affect both the local and systemic immune responses. The production of gut microbiota‐derived BEVs is regulated by host factors such as diet and antibiotic usage. Specifically, all aspects of nutrition, including macronutrients (protein, carbohydrates, and fat), micronutrients (vitamins and minerals), and food additives (the antimicrobial sodium benzoate), can regulate BEV production. This review summarizes current knowledge of the powerful links between nutrition, antibiotics, gut microbiota‐derived BEV, and their effects on immunity and disease development. It highlights the potential of targeting or utilizing gut microbiota‐derived BEV as a therapeutic intervention.
Dietary carbohydrate, particularly glucose, drives B cell lymphopoiesis and function
Publisher: Elsevier BV
Date: 08-2021
Interferon-independent increases in class I major histocompatibility complex antigen expression follow flavivirus infection
Publisher: Microbiology Society
Date: 10-1988
DOI: 10.1099/0022-1317-69-10-2535
Abstract: Infection of tertiary-passaged mouse embryo fibroblasts by four flaviviruses, West Nile (WNV), Kunjin, Murray Valley encephalitis and Japanese B encephalitis, resulted in a six- to 10-fold increase in the expression of in idual H-2K and H-2D class I major histocompatibility complex (MHC) antigens 16 to 48 h after infection. The mechanism(s) by which flaviviruses increased antigen expression has not been fully elucidated, but appears to be mediated partly independently of interferon-beta (IFN-beta) secretion, as anti-IFN-alpha beta antibodies partially inhibited the WNV-induced increase but totally prevented increases caused by the addition of (i) pure IFN-beta, (ii) IFN-beta-containing supernatants from WNV-infected mouse embryo fibroblasts (MEF), or (iii) polyinosinic-polycytidylic acid. Actinomycin D treatment of MEF, which inhibited mRNA synthesis by greater than 90% as determined by [3H]uridine uptake, totally inhibited the increased MHC expression caused by WNV infection. Thus, the increase in class I MHC antigen expression following infection is dependent upon cellular RNA synthesis.
Role of indoleamine 2,3-dioxygenase in health and disease
Publisher: Portland Press Ltd.
Date: 14-07-2015
DOI: 10.1042/CS20140392
Abstract: IDO1 (indoleamine 2,3-dioxygenase 1) is a member of a unique class of mammalian haem dioxygenases that catalyse the oxidative catabolism of the least-abundant essential amino acid, L-Trp (L-tryptophan), along the kynurenine pathway. Significant increases in knowledge have been recently gained with respect to understanding the fundamental biochemistry of IDO1 including its catalytic reaction mechanism, the scope of enzyme reactions it catalyses, the biochemical mechanisms controlling IDO1 expression and enzyme activity, and the discovery of enzyme inhibitors. Major advances in understanding the roles of IDO1 in physiology and disease have also been realised. IDO1 is recognised as a prominent immune regulatory enzyme capable of modulating immune cell activation status and phenotype via several molecular mechanisms including enzyme-dependent deprivation of L-Trp and its conversion into the aryl hydrocarbon receptor ligand kynurenine and other bioactive kynurenine pathway metabolites, or non-enzymatic cell signalling actions involving tyrosine phosphorylation of IDO1. Through these different modes of biochemical signalling, IDO1 regulates certain physiological functions (e.g. pregnancy) and modulates the pathogenesis and severity of erse conditions including chronic inflammation, infectious disease, allergic and autoimmune disorders, transplantation, neuropathology and cancer. In the present review, we detail the current understanding of IDO1’s catalytic actions and the biochemical mechanisms regulating IDO1 expression and activity. We also discuss the biological functions of IDO1 with a focus on the enzyme's immune-modulatory function, its medical implications in erse pathological settings and its utility as a therapeutic target.
Gliadin Nanoparticles Induce Immune Tolerance to Gliadin in Mouse Models of Celiac Disease
Publisher: Elsevier BV
Date: 05-2020
Immune Modulation by Flaviviruses
Publisher: Elsevier
Date: 2003
DOI: 10.1016/S0065-3527(03)60004-7
Abstract: Flaviviruses cause pleomorphic disease with significant morbidity and mortality worldwide. Interestingly, in contrast to most viruses, which subvert or avoid host immune systems, members of the neurotropic Japanese encephalitis serocomplex cause functional changes associated with increased efficacy of the immune response. These viruses induce increased cell surface expression of immune recognition molecules, including class I and II major histocompatibility complex (MHC) and various adhesion molecules. Increases are functional: infected cells are significantly more susceptible to both virus- and MHC-specific cytotoxic T cell lysis. Induced changes are modulated positively or negatively by Th1 and Th2 cytokines, as well as by cell cycle position and adherence status at infection. Infection also increases costimulatory molecule expression on Langerhans cells in the skin. Local interleukin-1 beta production causes accelerated migration of phenotypically altered Langerhans cells to local draining lymph nodes, where initiation of antiviral immune responses occur. The exact mechanism(s) of upregulation is unclear, but changes are associated with NF-kappa B activation and increased MHC and ICAM-1 gene transcription, independently of interferon (IFN) or other proinflammatory cytokines. Increased MHC and adhesion molecule expression may contribute to the pathogenesis of flavivirus encephalitis. Results from a murine model of flavivirus encephalitis developed in this laboratory suggest that fatal disease is immunopathological in nature, with IFN-gamma playing a crucial role. We hypothesize that these viruses may decoy the adaptive immune system into generating low-affinity T cells, which clear virus poorly, as part of their survival strategy. This may enable viral growth and immune escape in cycling cells, which do not significantly upregulate cell surface molecules.
Transcriptional regulation of major histocompatibility complex class I by flavivirus West Nile is dependent on NF-kappaB activation.
Publisher: Oxford University Press (OUP)
Date: 15-10-2001
DOI: 10.1086/323603
Abstract: Infection by the flavivirus West Nile (WNV) is associated with a virus-specific increase of major histocompatibility complex class I (MHC-I) molecules on the cell surface of diploid vertebrate cells. The increased MHC-I cell surface expression is functional and is associated with increased susceptibility to secondary WNV-immune and alloimmune cytotoxic T cells. WNV-induced up-regulation of cell surface MHC-I expression is associated with NF-kappaB activation and increased transcription of MHC-I mRNA. WNV infection increases luciferase activity of RAWa4 long terminal repeat (LTR) cells, which are transfected stably with a plasmid containing 2 NF-kappaB binding sites, the human immunodeficiency virus LTR linked to a luciferase reporter gene. The NF-kappaB-induced complexes are a p50 65 heterodimer and another faster migrating species containing p50 homodimers. WNV-induced activation of NF-kappaB and the up-regulation of MHC-I were blocked by the protein kinase C inhibitor H-7 and salicylate, both of which block phosphorylation of inhibitor kappaB.
Sertoli and germ cell development in hypogonadal (hpg) mice expressing transgenic follicle-stimulating hormone alone or in combination with testosterone
Publisher: The Endocrine Society
Date: 02-2003
Abstract: We recently created a novel transgenic (tg) model to examine the specific gonadal actions of FSH, distinct from LH effects, by expressing tg-FSH in gonadotropin-deficient hypogonadal (hpg) mice. Using this unique in vivo paradigm, we now describe the postnatal cellular development in seminiferous tubules selectively stimulated by tg-FSH alone or combined with testosterone (T). In the αβ.6 line, tg-FSH stimulated the maturation and proliferation (∼2-fold) of Sertoli cells in hpg testes. Total Sertoli cell numbers were also significantly increased (1.5-fold) independently of FSH effects by T treatment alone. Selective FSH activity in αβ.6 hpg testes increased total spermatogonia numbers 3-fold, which established a normal spermatogonia/Sertoli cell ratio. FSH also elevated meiotic spermatocyte numbers 7-fold, notably at pachytene (28-fold), but induced only limited numbers of postmeiotic haploid cells (absent in hpg controls) that arrested during spermatid elongation. In contrast, T treatment alone had little effect on postnatal spermatogonial proliferation but greatly enhanced meiotic progression with total spermatocytes increased 12-fold (pachytene 53-fold) relative to hpg testes, and total spermatid numbers 11-fold higher than tg-FSH hpg testes. Combining tg-FSH and T treatment had no further effect on Sertoli or spermatogonia numbers relative to FSH alone but had marked additive and synergistic effects on meiotic cells, particularly pachytene (107-fold more than hpg), to establish normal meiotic germ cell/Sertoli cell ratios. Furthermore, tg-FSH had a striking synergistic effect with T treatment on total spermatid numbers (19-fold higher than FSH alone), although spermatid to Sertoli cell ratios were not fully restored to normal, indicating elevated Sertoli cell numbers alone are insufficient to establish a maximal postmeiotic germ cell capacity. This unique model has allowed a detailed dissection of FSH in vivo activity alone or with T and provided compelling evidence that FSH effects on spermatogenesis are primarily via Sertoli and spermatogonial proliferation and the stimulation of meiotic and postmeiotic germ cell development in synergy with and dependent on T actions.
Role of MXRA8 in Ross River Virus Disease Pathogenesis
Publisher: American Society for Microbiology
Date: 25-04-2023
Abstract: Previous studies have shown the importance of the cell surface protein MXRA8 as an entry receptor for several different prominent alphaviruses such as CHIKV, RRV, MAYV, and ONNV. In particular, the role of MXRA8 in the tissue tropism, viral pathogenesis, and immune response of a CHIKV mouse model have already been briefly characterized.
Effects of β2
Publisher: Hindawi Limited
Date: 24-10-2011
DOI: 10.1155/2011/457169
Abstract: Rhinovirus-(RV-) induced asthma exacerbations account for high asthma-related health costs and morbidity in Australia. The cellular mechanism underlying this pathology is likely the result of RV-induced nuclear-factor-kappa-B-(NF-κB-) dependent inflammation. NF-κB may also be important in RV replication as inhibition of NF-κB inhibits replication of other viruses such as human immunodeficiency virus and cytomegalovirus. To establish the role of NF-κB inhibitors in RV-induced IL- 6 and IL-8 and RV replication, we used pharmacological inhibitors of NF-κB, and steroids and/or β 2 agonists were used for comparison. Primary human lung fibroblasts were infected with RV-16 in the presence of NF-κB inhibitors: BAY-117085 and dimethyl fumarate β 2 agonist: salmeterol and/or corticosteroids: dexamethasone fluticasone. RV-induced IL-6 and IL-8 and RV replication were assessed using ELISAs and virus titration assays. RV replicated and increased IL-6 and IL-8 release. Salmeterol increased, while dexamethasone and fluticasone decreased RV-induced IL-6 and IL-8 ( P 0.05 ). The NF-κB inhibitor BAY-117085 inhibited only RV-induced IL-6 ( P 0.05 ) and dimethyl fumarate did not alter RV-induced IL-6 and IL-8. Dimethylfumarate increased RV replication whilst other drugs did not alter RV replication. These data suggest that inhibition of NF-κB alone is unlikely to be an effective treatment compared to current asthma therapeutics.
Viruses and the immune system: Their roles in seizure cascade development
Publisher: Wiley
Date: 06-12-2008
DOI: 10.1111/J.1471-4159.2007.05171.X
Abstract: Viral encephalitis affects approximately 7.5 people/100 000 and carries a high rate of morbidity and mortality. Most patients with viral encephalitis will develop some form of seizure during the infectious process, and of those who survive encephalitic disease, approximately 4-20% will develop epilepsy. Arthropod-borne (arbo)viruses are the leading cause of viral encephalitis in the world today, with between 10% and 35% of patients infected with these viruses displaying some form of seizure. Several neurotropic DNA viruses, including Herpes and cytomegalovirus also commonly cause seizures in infected patients. In the clinical setting, the cause of seizures seen during viral encephalitis is usually attributed to acute febrile responses. However, it has become apparent that the mechanisms behind seizure generation during viral encephalitis are likely to be much more complicated. For ex le, CD4(+) and CD8(+) T cells possibly through their secretion of interferon-gamma, appear to play an important role in determining neuronal responses when challenged with kainic acid. In addition, the ability of the human immunodeficiency virus, transactivating protein to modulate NMDA signaling possibly triggering seizures, highlights the fact that elements of the antiviral response and even virally derived proteins are capable of directly manipulating neuronal function. Understanding the complex relationships between the CNS, the immune system, and invading pathogens is a critical step in understanding the pathogenesis of seizures seen during viral infections and informing the development of novel therapies.
West Nile Virus Infection Modulates the Expression of Class I and Class II MHC Antigens on Astrocytes in Vitro
Publisher: Wiley
Date: 11-1988
DOI: 10.1111/J.1749-6632.1988.TB27143.X
Abstract: A mass spectrometric (MS)-based strategy for antigen (Ag) identification and characterization of globally produced monoclonal antibodies (mAbs) is described. Mice were immunized with a mixture of native glycoproteins, isolated from the pooled plasma of patients with nonsmall cell lung cancer (NSCLC), to generate a library of IgG-secreting hybridomas. Prior to immunization, the pooled NSCLC plasma was subjected to 3-sequential steps of affinity fractionation, including high abundant plasma protein depletion, glycoprotein enrichment, and polyclonal antibody affinity chromatography normalization. In this paper, to demonstrate the high quality of the globally produced mAbs, we selected 3 mAbs of high differentiating power against a matched, pooled normal plasma s le. After production of large quantities of the mAbs from ascites fluids, Ag identification was achieved by immunoaffinity purification, SDS-PAGE, Western blotting, and MS analysis of in-gel digest products. One antigen was found to be complement factor H, and the other two were mapped to different subunits of haptoglobin (Hpt). The 2 Hpt mAbs were characterized in detail to assess the quality of the mAbs produced by the global strategy. The affinity of one of the mAbs to the Hpt native tetramer form was found to have a K(D) of roughly 10(-9) M and to be 2 orders of magnitude lower than the reduced form, demonstrating the power of the mAb proteomics technology in generating mAbs to the natural form of the proteins in blood. The binding of this mAb to the beta-chain of haptoglobin was also dependent on glycosylation on this chain. The characterization of mAbs in this work reveals that the global mAb proteomics process can generate high-quality lung cancer specific mAbs capable of recognizing proteins in their native state.
The generation of 1H-NMR-Detectable mobile lipid in stimulated lymphocytes: Relationship to cellular activation, the cell cycle, and phosphatidylcholine-specific phospholipase C
Publisher: Elsevier BV
Date: 10-1997
Abstract: Mobile lipids detected using 1H-NMR in stimulated lymphocytes were correlated with cell cycle phase, expression of the interleukin-2 receptor alpha and proliferation to assess the activation status of the lymphocytes. Mobile lipid levels, IL-2R alpha expression and proliferation increased after treatment with PMA and ionomycin. PMA or ionomycin stimulation alone induced increased IL-2R alpha expression but not proliferation. PMA- but not ionomycin-stimulation generated mobile lipid. Treatment with anti-CD3 antibody did not increase IL-2R alpha expression or proliferation but did generate increased amounts of mobile lipid. The cell cycle status of thymocytes treated with anti-CD3, PMA or ionomycin alone indicated an accumulation of the cells in the G1 phase of the cell cycle. The generation of mobile lipid was abrogated in anti-CD3 antibody-stimulated thymic lymphocytes but not in splenic lymphocytes, using a phosphatidylcholine-specific phospholipase C (PC-PLC) inhibitor which blocked cells in the G1/S phase of the cell cycle. This suggests that the 1H-NMR-detectable mobile lipid may be generated in anti-CD3 antibody-stimulated thymic lymphocytes by the action of PC-PLC activity via the catabolism of PC, in the absence of classical signs of activation.
Rhinovirus infection induces extracellular matrix protein deposition in asthmatic and nonasthmatic airway smooth muscle cells
Publisher: American Physiological Society
Date: 06-2011
DOI: 10.1152/AJPLUNG.00411.2010
Abstract: Airway remodeling, which includes increases in the extracellular matrix (ECM), is a characteristic feature of asthma and is correlated to disease severity. Rhinovirus (RV) infections are associated with increased risk of asthma development in young children and are the most common cause of asthma exacerbations. We examined whether viral infections can increase ECM deposition and whether this increased ECM modulates cell proliferation and migration. RV infection of nonasthmatic airway smooth muscle (ASM) cells significantly increased the deposition of fibronectin (40% increase, n = 12) and perlecan (80% increase, n = 14), while infection of asthmatic ASM cells significantly increased fibronectin (75% increase, n = 9) and collagen IV (15% increase, n = 9). We then treated the ASM cells with the Toll-like receptor (TLR) agonists polyinosinic:polycytidylic acid, imiquimod, and pure RV RNA and were able to show that the mechanism through which RV induced ECM deposition was via the activation of TLR3 and TLR7/8. Finally, we assessed whether the virus-induced ECM was bioactive by measuring the amount of migration and proliferation of virus-naive cells that seeded onto the ECM. Basically, ECM from asthmatic ASM cells induced twofold greater migration of virus-naive ASM cells than ECM from nonasthmatic ASM cells, and these rates of migration were further increased on RV-modulated ECM. Increased migration on the RV-modulated ECM was not due to increased cell proliferation, as RV-modulated ECM decreased the proliferation of virus-naive cells. Our results suggest that viruses may contribute to airway remodeling through increased ECM deposition, which in turn may contribute to increased ASM mass via increased cell migration.
Evaluating spectral cytometry for immune profiling in viral disease.
Publisher: Wiley
Date: 17-09-2020
DOI: 10.1002/CYTO.A.24211
TARGETING INFLAMMATORY MONOCYTES BY IMMUNE-MODIFYING NANOPARTICLES PREVENTS ACUTE KIDNEY ALLOGRAFT REJECTION.
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.KINT.2022.06.024
Abstract: Inflammatory monocytes are a major component of the cellular infiltrate in acutely rejecting human kidney allografts. Since immune-modifying nanoparticles (IMPs) bind to circulating inflammatory monocytes via the specific scavenger receptor MARCO, causing ersion to the spleen and subsequent apoptosis, we investigated the therapeutic potential of negatively charged, 500-nm diameter polystyrene IMPs to prevent kidney allograft rejection. Kidney transplants were performed from BALB/c (H2
The appearance of surface H-2 antigens on fetal and postnatal murine hepatocytes in vivo and in vitro: A comparative study of MHC control
Publisher: Springer Science and Business Media LLC
Date: 1986
DOI: 10.1007/BF00376517
Abstract: Approaches to the study of associative learning and interval timing have traditionally erged on methodological and theoretical levels of analysis. However, more recent attempts have been made to explain one class of phenomena in terms of the other using various single-process approaches. In this paper we suggest that an interactive dual-process approach might more accurately reflect underlying behavioral and neural processes. We will argue that timing in Pavlovian conditioning is best understood in terms of an abstract temporal code that is not a feature of the predictive stimulus (i.e., the conditioned stimulus, CS), per se. Rather, we assume that the time between the CS and the unconditioned stimulus (US) is encoded in the form of an abstract representation of this temporal interval produced as an output of a central multiple-oscillator interval timing system. As such, associations can then develop between the CS and this abstract temporal code in much the same way that the CS develops associations with different features of the US. To support the dual-process approach, we first show that exposure to a Pavlovian zero contingency procedure results in a failure to acquire new associations, not a failure to express learning due to some temporally defined performance mask. We also consider evidence that supports the abstract temporal coding idea in a US preexposure task, and, finally, present some evidence to encourage the dissociation between basic associative and temporal learning processes by exploring reward devaluation effects in a peak timing task.
Glomerular abnormalities in children undergoing orthotopic liver transplantation
Publisher: Springer Science and Business Media LLC
Date: 09-1992
DOI: 10.1007/BF00873994
PLX5622 Reduces Disease Severity in Lethal CNS Infection by Off-Target Inhibition of Peripheral Inflammatory Monocyte Production
Publisher: Frontiers Media SA
Date: 25-03-2022
DOI: 10.3389/FIMMU.2022.851556
Abstract: PLX5622 is a CSF-1R inhibitor and microglia-depleting reagent, widely used to investigate the biology of this central nervous system (CNS)-resident myeloid population, but the indirect or off-target effects of this agent remain largely unexplored. In a murine model of severe neuroinflammation induced by West Nile virus encephalitis (WNE), we showed PLX5622 efficiently depleted both microglia and a sub-population of border-associated macrophages in the CNS. However, PLX5622 also significantly depleted mature Ly6C hi monocytes in the bone marrow (BM), inhibiting their proliferation and lethal recruitment into the infected brain, reducing neuroinflammation and clinical disease scores. Notably, in addition, BM dendritic cell subsets, plasmacytoid DC and classical DC, were depleted differentially in infected and uninfected mice. Confirming its protective effect in WNE, cessation of PLX5622 treatment exacerbated disease scores and was associated with robust repopulation of microglia, rebound BM monopoiesis and markedly increased inflammatory monocyte infiltration into the CNS. Monoclonal anti-CSF-1R antibody blockade late in WNE also impeded BM monocyte proliferation and recruitment to the brain, suggesting that the protective effect of PLX5622 is via the inhibition of CSF-1R, rather than other kinase targets. Importantly, BrdU incorporation in PLX5622-treated mice, suggest remaining microglia proliferate independently of CSF-1 in WNE. Our study uncovers significantly broader effects of PLX5622 on the myeloid lineage beyond microglia depletion, advising caution in the interpretation of PLX5622 data as microglia-specific. However, this work also strikingly demonstrates the unexpected therapeutic potential of this molecule in CNS viral infection, as well as other monocyte-mediated diseases.
Designing drug-free biodegradable nanoparticles to modulate inflammatory monocytes and neutrophils for ameliorating inflammation
Publisher: Elsevier BV
Date: 04-2019
Langerhans cells migrate to local lymph nodes following cutaneous infection with an arbovirus
Publisher: Elsevier BV
Date: 03-2000
DOI: 10.1046/J.1523-1747.2000.00904.X
Abstract: Whereas there has been recent interest in interactions between dendritic cells and pathogenic viruses, the role of dendritic cells in the initiation of protective immunity to such organisms has not been elucidated. The aim of this study was to examine whether a resident dendritic cell population in the skin, Langerhans cells, respond to cutaneous viral infections which are effectively cleared by the immune system. We therefore characterized the ability of Langerhans cells to migrate to local draining lymph nodes following infection with the arthropod-borne viruses, West Nile virus or Semliki Forest virus. The data show that major histocompatibility complex class II+/NLDC145+/E-cadherin+ Langerhans cell numbers are increased in the draining lymph nodes of infected mice and this increase is accompanied by a concomitant decrease in the Langerhans cell density in the epidermis. Langerhans cell migration is associated with an accumulation of leukocytes in the lymph node, which is one of the earliest events in the initiation of an immune response. Both the migratory response and the draining lymph node leukocyte accumulation were abrogated if ultraviolet-inactivated instead of live viruses were used, suggesting the activation and subsequent migration of Langerhans cells requires a live, replicating antigen. Our findings are likely to have wider implications for the development of epidermally delivered vaccines and suggest that mobilization of dendritic cells may be involved in the development of immune responses to arthropod-borne viruses.
CXCR3 signaling reduces the severity of experimental autoimmune encephalomyelitis by controlling the parenchymal distribution of effector and regulatory T cells in the central nervous system
Publisher: The American Association of Immunologists
Date: 09-2007
DOI: 10.4049/JIMMUNOL.179.5.2774
Abstract: The chemokine receptor CXCR3 promotes the trafficking of activated T and NK cells in response to three ligands, CXCL9, CXCL10, and CXCL11. Although these chemokines are produced in the CNS in multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), their role in the pathogenesis of CNS autoimmunity is unresolved. We examined the function of CXCR3 signaling in EAE using mice that were deficient for CXCR3 (CXCR3−/−). The time to onset and peak disease severity were similar for CXCR3−/− and wild-type (WT) animals however, CXCR3−/− mice had more severe chronic disease with increased demyelination and axonal damage. The inflammatory lesions in WT mice consisted of well-demarcated perivascular mononuclear cell infiltrates, mainly in the spinal cord and cerebellum. In CXCR3−/− mice, these lesions were more widespread throughout the CNS and were diffused and poorly organized, with T cells and highly activated microglia/macrophages scattered throughout the white matter. Although the number of CD4+ and CD8+ T cells infiltrating the CNS were similar in CXCR3−/− and WT mice, Foxp3+ regulatory T cells were significantly reduced in number and dispersed in CXCR3−/− mice. The expression of various chemokine and cytokine genes in the CNS was similar in CXCR3−/− and WT mice. The genes for the CXCR3 ligands were expressed predominantly in and/or immediately surrounding the mononuclear cell infiltrates. We conclude that in EAE, CXCR3 signaling constrains T cells to the perivascular space in the CNS and augments regulatory T cell recruitment and effector T cell interaction, thus limiting autoimmune-mediated tissue damage.
Using a Collateral Damage Model to Explain Survival Data in West Nile Virus Infections
Publisher: Scientific Research Publishing, Inc.
Date: 2016
FHL1 promotes chikungunya and o’nyong-nyong virus infection and pathogenesis with implications for alphavirus vaccine design
Publisher: Springer Science and Business Media LLC
Date: 26-10-2023
The Immunopathogenesis of Neurotropic Flavivirus Infection
Publisher: InTech
Date: 30-09-2011
DOI: 10.5772/22243
Flavivirus induces MHC antigen on human myoblasts: A model of autoimmune myositis?
Publisher: Wiley
Date: 11-1992
Therapeutic inflammatory monocyte modulation using immune-modifying microparticles.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 15-01-2014
DOI: 10.1126/SCITRANSLMED.3007563
Abstract: Negatively charged immune-modifying microparticles bind to the scavenger receptor MARCO on inflammatory monocytes, resulting in their apoptosis and reduced inflammatory damage in a range of diseases.
ChronoClust: Density-based clustering and cluster tracking in high-dimensional time-series data
Publisher: Elsevier BV
Date: 06-2019
Structural selectivity and molecular nature of L-glutamate transport in cultured human fibroblasts
Publisher: Elsevier BV
Date: 05-1998
Abstract: Uptake of L-[3H]glutamate by monolayers of fibroblasts cultured from human embryonic skin has been studied in the presence of several nonradioactive structural analogs of glutamate and aspartate. Results have suggested that the structural specificites of glutamate transporters in cultured human fibroblasts are similar to those of glutamate transporters in the mammalian brain. Only subtle differences have been detected: in the mammalian cerebral cortex, enantiomers of threo-3-hydroxyaspartate are almost equipotent as inhibitors of L-[3H]glutamate uptake while, in human fibroblasts, the D-isomer has been found to be an order of magnitude less potent than the corresponding L-isomer. Kinetic analysis of a model in which substrates are recognized by the glutamate transporter binding site(s) as both alpha- and beta-amino acids indicated that such a mechanism cannot explain the apparent negative cooperativity characterizing the effects of D- and L-aspartate. Molecular modeling has been used to estimate the optimum conformation of L-glutamate as it interacts with the transporter(s). Flow cytometry has indicated that all fibroblasts in culture express at least moderate levels of four glutamate transporters cloned from human brain. Small subpopulations (< 3%) of cells, however, were strongly labeled with antibodies against EAAT1 (GLAST) and EAAT2 (GLT-1) transporters. We conclude that these two transporters--known to be strongly expressed in brain tissue--can be principally responsible for the "high affinity" transport of glutamate also in nonneural cells.
Rhinovirus exposure impairs immune responses to bacterial products in human alveolar macrophages
Publisher: BMJ
Date: 02-2008
Abstract: Rhinovirus infection is responsible for considerable morbidity and mortality as the major cause of exacerbations of asthma, and is also known to induce exacerbations of cystic fibrosis and chronic obstructive pulmonary disease. Exacerbations of these diseases are also frequently associated with bacterial and atypical bacterial infection. Alveolar macrophages are the major immune cells in the airways and are important in defence against bacterial infections. The authors investigated whether rhinovirus modifies cytokine release, the pattern recognition receptor expression and phagocytosis by human alveolar macrophages in response to bacterial products. Viable rhinovirus was detected in macrophages up to 3 days after exposure and viral RNA expression persisted for 10 days. Infectious but not UV inactivated rhinovirus increased tumour necrosis factor α (TNFα) and interleukin (IL)8 release by macrophages. In contrast, infectious rhinovirus impaired lipopolysaccharide and lipoteichoic acid induced TNFα and IL8 secretion by macrophages. Rhinovirus induced impairment of macrophage antibacterial immune responses did not involve IL10, prostaglandin E 2 or downregulation of Toll-like receptor 2. Furthermore, the macrophage phagocytic response to labelled bacterial particles, but not to latex beads, was impaired. The authors have identified impairment of cytokine responses to bacterial lipopolysaccharide and lipoteichoic acid by alveolar macrophages in response to infectious rhinovirus. Virus induced impairment of antibacterial host defence has important implications in the pathogenesis of exacerbations of respiratory diseases.
Flow cytometry of plant cells with applications in large-scale bioprocessing
Publisher: Elsevier BV
Date: 04-1999
DOI: 10.1016/S0734-9750(98)00014-7
Abstract: In recent years, there has been a significant upsurge in the application of flow cytometry to plant cells and plant cell cultures. As well as a range of uses in plant biology, flow cytometry offers many advantages for monitoring plant cell cultures used in large-scale bioprocessing operations. This review summarizes the current status of the field, concentrating on methods for DNA measurement and multiparameter cell cycle analysis. Techniques for screening and selection of elite cell lines with high productivity of secondary metabolites are also addressed.
IRF9 Prevents CD8 + T Cell Exhaustion in an Extrinsic Manner during Acute Lymphocytic Choriomeningitis Virus Infection
Publisher: American Society for Microbiology
Date: 15-11-2017
DOI: 10.1128/JVI.01219-17
Abstract: Effective CD8 + T cell responses play an important role in determining the course of a viral infection. Overwhelming antigen exposure can result in suboptimal CD8 + T cell responses, leading to chronic infection. This altered CD8 + T cell differentiation state, termed exhaustion, is characterized by reduced effector function, upregulation of inhibitory receptors, and altered expression of transcription factors. Prevention of overwhelming antigen exposure to limit CD8 + T cell exhaustion is of significant interest for the control of chronic infection. The transcription factor interferon regulatory factor 9 (IRF9) is a component of type I interferon (IFN-I) signaling downstream of the IFN-I receptor (IFNAR). Using acute infection of mice with lymphocytic choriomeningitis virus (LCMV) strain Armstrong, we show here that IRF9 limited early LCMV replication by regulating expression of interferon-stimulated genes and IFN-I and by controlling levels of IRF7, a transcription factor essential for IFN-I production. Infection of IRF9- or IFNAR-deficient mice led to a loss of early restriction of viral replication and impaired antiviral responses in dendritic cells, resulting in CD8 + T cell exhaustion and chronic infection. Differences in the antiviral activities of IRF9- and IFNAR-deficient mice and dendritic cells provided further evidence of IRF9-independent IFN-I signaling. Thus, our findings illustrate a CD8 + T cell-extrinsic function for IRF9, as a signaling factor downstream of IFNAR, in preventing overwhelming antigen exposure resulting in CD8 + T cell exhaustion and, ultimately, chronic infection. IMPORTANCE During early viral infection, overwhelming antigen exposure can cause functional exhaustion of CD8 + T cells and lead to chronic infection. Here we show that the transcription factor interferon regulatory factor 9 (IRF9) plays a decisive role in preventing CD8 + T cell exhaustion. Using acute infection of mice with LCMV strain Armstrong, we found that IRF9 limited early LCMV replication by regulating expression of interferon-stimulated genes and Irf7 , encoding a transcription factor crucial for type I interferon (IFN-I) production, as well as by controlling the levels of IFN-I. Infection of IRF9-deficient mice led to a chronic infection that was accompanied by CD8 + T cell exhaustion due to defects extrinsic to T cells. Our findings illustrate an essential role for IRF9, as a mediator downstream of IFNAR, in preventing overwhelming antigen exposure causing CD8 + T cell exhaustion and leading to chronic viral infection.
Basic insights into Zika virus infection of neuroglial and brain endothelial cells
Publisher: Microbiology Society
Date: 06-2020
DOI: 10.1099/JGV.0.001416
Abstract: Zika virus (ZIKV) has recently emerged as an important human pathogen due to the strong evidence that it causes disease of the central nervous system, particularly microcephaly and Guillain–Barré syndrome. The pathogenesis of disease, including mechanisms of neuroinvasion, may include both invasion via the blood–brain barrier and via peripheral (including cranial) nerves. Cellular responses to infection are also poorly understood. This study characterizes the in vitro infection of laboratory-adapted ZIKV African MR766 and two Asian strains of (1) brain endothelial cells (hCMEC/D3 cell line) and (2) olfactory ensheathing cells (OECs) (the neuroglia populating cranial nerve I and the olfactory bulb both human and mouse OEC lines) in comparison to kidney epithelial cells (Vero cells, in which ZIKV infection is well characterized). Readouts included infection kinetics, intracellular virus localization, viral persistence and cytokine responses. Although not as high as in Vero cells, viral titres exceeded 10 4 plaque-forming units (p.f.u.) ml −1 in the endothelial/neuroglial cell types, except hOECs. Despite these substantial titres, a relatively small proportion of neuroglial cells were primarily infected. Immunolabelling of infected cells revealed localization of the ZIKV envelope and NS3 proteins in the cytoplasm NS3 staining overlapped with that of dsRNA replication intermediate and the endoplasmic reticulum (ER). Infected OECs and endothelial cells produced high levels of pro-inflammatory chemokines. Nevertheless, ZIKV was also able to establish persistent infection in hOEC and hCMEC/D3 cells. Taken together, these results provide basic insights into ZIKV infection of endothelial and neuroglial cells and will form the basis for further study of ZIKV disease mechanisms.
Specific inhibition of NLRP3 in chikungunya disease reveals a role for inflammasomes in alphavirus-induced inflammation
Publisher: Springer Science and Business Media LLC
Date: 28-08-2017
DOI: 10.1038/S41564-017-0015-4
Abstract: Mosquito-borne viruses can cause severe inflammatory diseases and there are limited therapeutic solutions targeted specifically at virus-induced inflammation. Chikungunya virus (CHIKV), a re-emerging alphavirus responsible for several outbreaks worldwide in the past decade, causes debilitating joint inflammation and severe pain. Here, we show that CHIKV infection activates the NLRP3 inflammasome in humans and mice. Peripheral blood mononuclear cells isolated from CHIKV-infected patients showed elevated NLRP3, caspase-1 and interleukin-18 messenger RNA expression and, using a mouse model of CHIKV infection, we found that high NLRP3 expression was associated with peak inflammatory symptoms. Inhibition of NLRP3 activation using the small-molecule inhibitor MCC950 resulted in reduced CHIKV-induced inflammation and abrogated osteoclastogenic bone loss and myositis, but did not affect in vivo viral replication. Mice treated with MCC950 displayed lower expression levels of the cytokines interleukin-6, chemokine ligand 2 and tumour necrosis factor in joint tissue. Interestingly, MCC950 treatment abrogated disease signs in mice infected with a related arthritogenic alphavirus, Ross River virus, but not in mice infected with West Nile virus-a flavivirus. Here, using mouse models of alphavirus-induced musculoskeletal disease, we demonstrate that NLRP3 inhibition in vivo can reduce inflammatory pathology and that further development of therapeutic solutions targeting inflammasome function could help treat arboviral diseases.
Microglia and monocytes in inflammatory CNS disease: integrating phenotype and function
Publisher: Springer Science and Business Media LLC
Date: 12-2021
DOI: 10.1007/S00401-021-02384-2
Abstract: In neurological diseases, the actions of microglia, the resident myeloid cells of the CNS parenchyma, may erge from, or intersect with, those of recruited monocytes to drive immune-mediated pathology. However, defining the precise roles of each cell type has historically been impeded by the lack of discriminating markers and experimental systems capable of accurately identifying them. Our ability to distinguish microglia from monocytes in neuroinflammation has advanced with single-cell technologies, new markers and drugs that identify and deplete them, respectively. Nevertheless, the focus of in idual studies on particular cell types, diseases or experimental approaches has limited our ability to connect phenotype and function more widely and across erse CNS pathologies. Here, we critically review, tabulate and integrate the disease-specific functions and immune profiles of microglia and monocytes to provide a comprehensive atlas of myeloid responses in viral encephalitis, demyelination, neurodegeneration and ischemic injury. In emphasizing the differential roles of microglia and monocytes in the severe neuroinflammatory disease of viral encephalitis, we connect inflammatory pathways common to equally incapacitating diseases with less severe inflammation. We examine these findings in the context of human studies and highlight the benefits and inherent limitations of animal models that may impede or facilitate clinical translation. This enables us to highlight common and contrasting, non-redundant and often opposing roles of microglia and monocytes in disease that could be targeted therapeutically.
Zika Virus: Mechanisms of Infection During Pregnancy
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.TIM.2017.05.005
Abstract: Immune status changes during pregnancy, with pro-inflammatory and anti-inflammatory contexts at different stages, making pregnant women potentially more susceptible to various infections. Infection by Zika virus during pregnancy can cause developmental damage to the fetus, and the altered immune response during pregnancy could contribute to disease during Zika infection.
Class I major histocompatibility complex antigen expression on early murine trophoblast and its induction by lymphokines in vitro. II. The role of gamma interferon in the responses of primary and secondary giant cells
Publisher: Elsevier BV
Date: 09-1987
DOI: 10.1016/0165-0378(87)90077-5
Abstract: The induction of paternal Class I and II MHC antigens by crude lymphokine preparations or purified recombinant gamma interferon was investigated on (C57BL/6J X CBA/H)F1 primary and secondary trophoblast giant cell outgrowths from 3.5-day post-coital (pc) blastocyst and 7.5-day pc ectoplacental cone preparations, respectively, using sensitive immunogold labelling techniques and electron microscopy. Class I MHC (but not Class II) antigens could readily be induced on secondary trophoblast giant cells, by incubation in vitro with gamma interferon for 40 h. However, repeated attempts to induce detectable MHC antigens on primary trophoblast giant cells failed. Mock-treated (C57BL/6J X CBA/H)F1 secondary trophoblast giant cell control preparations failed to express detectable MHC antigens. These findings suggest that, at the time of implantation, there is a time window during which MHC antigens are neither expressed constitutively nor are inducible by soluble factors which normally modulate cell surface MHC antigen concentration.
GPR109A expressed on medullary thymic epithelial cells affects thymic Treg development
Publisher: Wiley
Date: 07-09-2023
Abstract: Regulatory T cells (Treg) maintain immune homeostasis due to their anti‐inflammatory functions. They can be generated either centrally in the thymus or in peripheral organs. Metabolites such as short chain fatty acids produced by intestinal microbiota can induce peripheral Treg differentiation, by activating G‐protein‐coupled‐receptors like GPR109A. In this study, we identified a novel role for GPR109A on thymic Treg development. We found that Gpr109a −/− mice had increased Treg under basal conditions in multiple organs compared to wild type (WT) mice. GPR109A was not expressed on T cells but on medullary thymic epithelial cells (mTECs), as revealed by single cell RNA sequencing in both mice and humans and confirmed by flow cytometry in mice. mTECs isolated from Gpr109a −/− mice had higher expression of autoimmune regulator (AIRE), the key regulator of Treg development, while the subset of mTECs that did not express Gpr109a in the WT displayed increased Aire expression and also enhanced signalling related to mTEC functionality. Increased thymic Treg in Gpr109a −/− mice was associated with protection from experimental autoimmune encephalomyelitis, with ameliorated clinical signs and reduced inflammation. This work identifies a novel role for GPR109A and possibly the gut microbiota, on thymic Treg development via its regulation of mTECs. This article is protected by copyright. All rights reserved
The plasticity of inflammatory monocyte responses to the inflamed central nervous system.
Publisher: Elsevier BV
Date: 09-2014
Flow cytometric analysis of immunogold cell surface label
Publisher: Wiley
Date: 09-1984
Abstract: Goat antimouse immunoglobulin antibodies conjugated to colloidal 40-nm gold particles were used to label mouse spleen lymphocytes. The labeled cells were analysed with a flow cytometer, equipped with an argon-ion laser and a (0.5 mW) helium-neon laser. The right-angle (90 degrees) light scatter signal of the red (632.8 nm) helium-neon light was enhanced more than tenfold by the gold label. Dual labeling with gold and fluorescein isothiocyanate (FITC) showed no interference between the two labels. Thus immunogold provides a nonfluorescent cell surface label that can be combined with other cell labels for multiparametrical cell analysis.
Flavivirus infection up-regulates the expression of class I and class II major histocompatibility antigens on and enhances T cell recognition of astrocytes in vitro
Publisher: Elsevier BV
Date: 02-1989
Fluorescent nanodiamonds for biological applications
Publisher: IEEE
Date: 08-2011
Differential target cell susceptibility to SFV-immune cytotoxic T-cells
Publisher: Springer Science and Business Media LLC
Date: 03-1989
DOI: 10.1007/BF01313882
Apoptosis of vascular smooth muscle cells induced by cholesterol and its oxides in vitro and in vivo
Publisher: Elsevier BV
Date: 02-2000
DOI: 10.1016/S0021-9150(99)00286-5
Abstract: The ability of cholesterol and its oxides to induce apoptosis in vascular smooth muscle cells in tissue culture and in a rabbit model of atherosclerosis was evaluated. Apoptosis was detected using DNA laddering and in situ end-labelling of fragmented DNA. Cholesterol oxides, but not cholesterol, were found to inhibit proliferation and induce apoptosis of vascular smooth muscle cells in tissue culture. 7-ketocholesterol was found to be the most potent inhibitor of proliferation, while 25-hydroxycholesterol was found to be the most potent inducer of apoptosis. These data suggest that the inhibition of proliferation and the induction of apoptosis by cholesterol oxides within vascular smooth muscle cells use different pathways, suggesting a differential role for these cholesterol oxides within the arterial wall. Cholesterol feeding after balloon injury in a rabbit model of atherosclerosis is known to result in the accumulation of cholesterol oxides. However, we found that cholesterol feeding had no effect on the level of apoptosis in the rabbit aortic wall after balloon injury, suggesting that the major factor determining apoptosis in our model was the balloon injury.
Oncogenic Action of Secreted Phospholipase A2 in Prostate Cancer
Publisher: American Association for Cancer Research (AACR)
Date: 10-2004
DOI: 10.1158/0008-5472.CAN-03-3018
Abstract: Mortality from prostate cancer is associated with progression of tumors to androgen-independent growth and metastasis. Eicosanoid products of both the cyclooxygenase (COX) and lipoxygenase (LOX) pathways are important mediators of the proliferation of prostate cancer cells in culture and regulate tumor vascularization and metastasis in animal models. Pharmacologic agents that block either COX or LOX products effectively reduce the size of prostate cancer xenografts. Phospholipase A2 (PLA2) enzymes regulate the provision of arachidonic acid to both COX- and LOX-derived eicosanoids, and a secreted form of the enzyme (sPLA2-IIA) is elevated in prostate cancer tissues. Here, we show by immunohistochemistry, in patients receiving androgen ablation therapy, that sPLA2-IIA remains elevated in remaining cancer cells relative to benign glands after treatment. Furthermore, sPLA2-IIA expression seen in benign glands is substantially decreased after androgen depletion, whereas cytosolic PLA2-α (cPLA2-α) levels are unchanged. sPLA2-IIA mRNA expression is detectable and inducible by androgen (0.01–10 nmol/L) in the androgen-sensitive cell line LNCaP, and exogenous addition of sPLA2-IIA (1–100 nmol/L), but not an inactive sPLA2-IIA mutant (H48Q), results in a dose-dependent increase in cell numbers or the fraction of cells in G2-M phase, which is inhibited by sPLA2-IIA-selective inhibitors. The effect of exogenous sPLA2-IIA can also be blocked by inhibition of cPLA2-α, suggesting a role for cPLA2-α in mediating sPLA2-IIΑ action. sPLA2-IIA inhibitors suppressed basal proliferation in LNCaP cells and in the androgen-independent, sPLA2-positive cell line PC3 but not in the sPLA2-IIA-negative androgen-independent cell line DU145. Established PC3 xenograft tumors grew more slowly in mice treated with sPLA2-IIA inhibitors than those treated with saline only. The PLA2 enzymes, and sPLA2-IIA in particular, thus represent important targets for the treatment of sPLA2-IIA-positive androgen-independent prostate cancer.
Luminescent nanodiamonds for biomedical applications
Publisher: Springer Science and Business Media LLC
Date: 11-10-2011
TrackSOM: mapping immune response dynamics through sequential clustering of time- and disease-course single-cell cytometry data
Publisher: Cold Spring Harbor Laboratory
Date: 09-06-2021
DOI: 10.1101/2021.06.08.447468
Abstract: Mapping the dynamics of immune cell populations over time or disease-course is key to understanding immunopathogenesis and devising putative interventions. We present TrackSOM, an algorithm which delineates cellular populations and tracks their development over a time- or disease-course of cytometry datasets. We demonstrate TrackSOM-enabled elucidation of the immune response to West Nile Virus infection in mice, uncovering heterogeneous sub-populations of immune cells and relating their functional evolution to disease severity. TrackSOM is easy to use, encompasses few parameters, is quick to execute, and enables an integrative and dynamic overview of the immune system kinetics that underlie disease progression and/or resolution.
Immunodeficient mice recover from infection with vaccinia virus expressing interferon‐γ
Publisher: Wiley
Date: 1990
Abstract: Recombinant vaccinia viruses (VV)-encoding murine interferon-gamma (IFN-gamma) were constructed and the effect of virus-encoded IFN-gamma on the immune response towards VV in vivo investigated. In athymic nude mice and sublethally irradiated euthymic mice, IFN-gamma expression by VV enabled the mice to recover from the infection, whereas mice infected with the control virus died. In normal CBA/H mice also, the growth of VV was greatly reduced and it was cleared faster from mouse organs than the control virus. Natural killer (NK) cell responses in these mice were not enhanced suggesting that this recovery is not NK cell mediated. Other possible mechanisms and implications of this observation are discussed.
Impact of Dietary Fiber on West Nile Virus Infection
Publisher: Frontiers Media SA
Date: 28-02-2022
DOI: 10.3389/FIMMU.2022.784486
Abstract: Dietary fiber supports healthy gut bacteria and their production of short-chain fatty acids (SCFA), which promote anti-inflammatory cell development, in particular, regulatory T cells. It is thus beneficial in many diseases, including influenza infection. While disruption of the gut microbiota by antibiotic treatment aggravates West Nile Virus (WNV) disease, whether dietary fiber is beneficial is unknown. WNV is a widely-distributed neurotropic flavivirus that recruits inflammatory monocytes into the brain, causing life-threatening encephalitis. To investigate the impact of dietary fiber on WNV encephalitis, mice were fed on diets deficient or enriched with dietary fiber for two weeks prior to inoculation with WNV. To induce encephalitis, mice were inoculated intranasally with WNV and maintained on these diets. Despite increased fecal SCFA acetate and changes in gut microbiota composition, dietary fiber did not affect clinical scores, leukocyte infiltration into the brain, or survival. After the brain, highest virus loads were measured in the colon in neurons of the submucosal and myenteric plexuses. Associated with this, there was disrupted gut homeostasis, with shorter colon length and higher local inflammatory cytokine levels, which were not affected by dietary fiber. Thus, fiber supplementation is not effective in WNV encephalitis.
H.E.S.S. Follow-up Observations of GRB 221009A
Publisher: American Astronomical Society
Date: 03-2023
Abstract: GRB 221009A is the brightest gamma-ray burst (GRB) ever detected. To probe the very-high-energy (VHE GeV) emission, the High Energy Stereoscopic System (H.E.S.S.) began observations 53 hr after the triggering event, when the brightness of the moonlight no longer precluded observations. We derive differential and integral upper limits using H.E.S.S. data from the third, fourth, and ninth nights after the initial GRB detection, after applying atmospheric corrections. The combined observations yield an integral energy flux upper limit of Φ UL 95 % = 9.7 × 10 − 12 erg cm − 2 s − 1 above E thr = 650 GeV. The constraints derived from the H.E.S.S. observations complement the available multiwavelength data. The radio to X-ray data are consistent with synchrotron emission from a single electron population, with the peak in the spectral energy distribution occurring above the X-ray band. Compared to the VHE-bright GRB 190829A, the upper limits for GRB 221009A imply a smaller gamma-ray to X-ray flux ratio in the afterglow. Even in the absence of a detection, the H.E.S.S. upper limits thus contribute to the multiwavelength picture of GRB 221009A, effectively ruling out an IC-dominated scenario.
Cytotoxicity and non-specific cellular uptake of bare and surface-modified upconversion nanoparticles in human skin cells
Publisher: Springer Science and Business Media LLC
Date: 23-01-2015
Mice Deficient in STAT1 but Not STAT2 or IRF9 Develop a Lethal CD4+ T-Cell-Mediated Disease following Infection with Lymphocytic Choriomeningitis Virus
Publisher: American Society for Microbiology
Date: 15-06-2012
DOI: 10.1128/JVI.07147-11
Abstract: Interferon (IFN) signaling is crucial for antiviral immunity. While type I IFN signaling is mediated by STAT1, STAT2, and IRF9, type II IFN signaling requires only STAT1. Here, we studied the roles of these signaling factors in the host response to systemic infection with lymphocytic choriomeningitis virus (LCMV). In wild-type (WT) mice and mice lacking either STAT2 or IRF9, LCMV infection was nonlethal, and the virus either was cleared (WT) or established persistence (STAT2 knockout [KO] and IRF9 KO). However, in the case of STAT1 KO mice, LCMV infection was lethal and accompanied by severe multiorgan immune pathology, elevated expression of various cytokine genes in tissues, and cytokines in the serum. This lethal phenotype was unaltered by the coabsence of the gamma interferon (IFN-γ) receptor and hence was not dependent on IFN-γ. Equally, the disease was not due to a combined defect in type I and type II IFN signaling, as IRF9 KO mice lacking the IFN-γ receptor survived infection with LCMV. Clearance of LCMV is mediated normally by CD8 + T cells. However, the depletion of these cells in LCMV-infected STAT1 KO mice was delayed, but did not prevent, lethality. In contrast, depletion of CD4 + T cells prevented lethality in LCMV-infected STAT1 KO mice and was associated with a reduction in tissue immune pathology. These studies highlight a fundamental difference in the role of STAT1 versus STAT2 and IRF9. While all three factors are required to limit viral replication and spread, only STAT1 has the unique function of preventing the emergence of a lethal antiviral CD4 + T-cell response.
High-Dimensional Fluorescence Cytometry.
Publisher: Wiley
Date: 11-2017
DOI: 10.1002/CPIM.37
Abstract: The immune system consists of a complex network of cells, all expressing a wide range of surface and/or intracellular proteins. Using flow cytometry, these cells can be analyzed by labeling with fluorophore‐conjugated antibodies. The recent expansion of fluorescence flow cytometry technology, in conjunction with the ever‐expanding understanding of the complexity of the immune system, has led to the generation of larger high‐dimensional fluorescence flow cytometry panels. However, as panel size and complexity increases, so too does the difficulty involved in constructing high‐quality panels, in addition to the challenges of analyzing such high‐dimensional datasets. As such, this unit seeks to review the key principles involved in building high‐dimensional panels, as well as to guide users through the process of building and analyzing quality panels. Here, cytometer configuration, fluorophore brightness, spreading error, antigen density, choosing the best conjugates, titration, optimization, and data analysis will all be addressed. © 2017 by John Wiley & Sons, Inc.
Expression of Fas and FasL in human serous ovarian epithelial tumors
Publisher: Elsevier BV
Date: 2003
DOI: 10.1053/HUPA.2003.7
Fc receptors in antibody-dependent enhancement of viral infections.
Publisher: Wiley
Date: 26-10-2015
DOI: 10.1111/IMR.12367
Discovery of a radiation component from the Vela pulsar reaching 20 teraelectronvolts
Publisher: Springer Science and Business Media LLC
Date: 05-10-2023
Influenza virus inhibits amiloride-sensitive Na+ channels in respiratory epithelia
Publisher: Proceedings of the National Academy of Sciences
Date: 08-2000
Abstract: Many pathogens causing diarrhea do so by modulating ion transport in the gut. Respiratory pathogens are similarly associated with disturbances of fluid balance in the respiratory tract, although it is not known whether they too act by altering epithelial ion transport. Here we show that influenza virus A/PR/8/34 inhibits the amiloride-sensitive Na + current across mouse tracheal epithelium with a half-time of about 60 min. We further show that the inhibitory effect of the influenza virus is caused by the binding of viral hemagglutinin to a cell-surface receptor, which then activates phospholipase C and protein kinase C. Given the importance of epithelial Na + channels in controlling the amount of fluid in the respiratory tract, we suggest that down-regulation of Na + channels induced by influenza virus may play a role in the fluid transport abnormalities that are associated with influenza infections.
Interferon gamma induces intercellular adhesion molecule-1 on murine midterm trophoblast and enhances susceptibility to specific lysis by paternally directed allo-immune cytotoxic T cells
Publisher: Oxford University Press (OUP)
Date: 12-1994
DOI: 10.1095/BIOLREPROD51.6.1164
Abstract: Expression and function of intercellular adhesion molecule-1 (ICAM-1) on murine trophoblast cells and its regulation by interferon gamma (IFN-gamma) were investigated. Flow cytometry was used to detect ICAM-1 and class I major histocompatibility complex (MHC) antigen expression, while a 51Cr release assay was used to investigate the role of ICAM-1 in cytotoxic T lymphocyte (CTL)-mediated lysis and the effect of anti-ICAM-1 antibody blockade on lysis. We found that murine trophoblasts cells from midterm pregnancy (Day 14 postcoitum) express low or undetectable ICAM-1 and MHC antigens but that these are readily inducible by IFN-gamma. Untreated cells resisted lysis by allospecific CTL however, after treatment with IFN-gamma for 72 h, these trophoblasts were readily susceptible to lysis by allospecific CTL. The lysis was significantly reduced by anti-ICAM-1 antibody blocking. This finding which indicates that ICAM-1 can take part in CTL-mediated lysis of midterm trophoblast, has potentially important implications in vivo for the immunological relationship between mother and fetus.
A comparison of the chemical analyses of cell lipids with their complete proton NMR spectrum
Publisher: Wiley
Date: 06-1987
Abstract: Whole cells are made up of molecules in different environments to which NMR spectroscopy is sensitive. In particular, malignant and transformed cells contain lipids not only in bilayers but in isotropically tumbling domains which give rise to high-resolution spectra. We have recently developed a technique for simultaneously analyzing broadline and high-resolution signals (M. Bloom, K. T. Holmes, C. E. Mountford, and P. G. Williams, J. Magn. Reson., in press) and we report here its application to a range of rat, mouse, and human cell lines. Some selected features of the NMR spectra were compared with the chemical analysis of the whole-cell lipid. We found that in general the proportion of protons in the narrow methylene resonance at 1.3 ppm increased with the neutral lipid content of the cells. This peak was chosen because its T2 relaxation behavior correlates with metastatic potential in a rat model system. This new technique could be applied to other high-resolution components both in healthy and in diseased states.
Target cell lysis by natural killer cells is influenced by beta 2-microglobulin expression.
Publisher: Wiley
Date: 07-1989
DOI: 10.1111/J.1365-3083.1989.TB01184.X
Abstract: Natural killer (NK) cells form part of the vertebrate defence against viruses and tumours, but show only limited specificity. The molecule(s) recognized by NK cells on target cells are at present unknown. Major histocompatibility complex (MHC) class I antigen concentration on target cells is inversely correlated with NK cell lysis. Here we show that MHC class I-unassociated beta 2-microglobulin (beta 2-m) expression is involved in NK cell-target cell interaction. Two human MHC class I negative cell lines, Daudi and K562, are differentially susceptible to NK cell lysis. Daudi cells are beta 2-m-negative and resistant to NK lysis, K562 are beta 2-m-positive and highly susceptible to lysis by NK cells. Interferon (IFN) treatment augments beta 2-m expression and NK lysis of K562, but not in Daudi cells. NK cell lysis of K562, but not YAC-1 cells, can be inhibited by monoclonal anti-human beta 2-m antibody. Furthermore, susceptibility of mouse embryo fibroblasts (MEF) to NK lysis can be increased by infection with recombinant vaccinia virus expressing the human beta 2-m gene.
A model of auto immune response
Publisher: Springer Science and Business Media LLC
Date: 06-2017
High-parameter cytometry unmasks microglial cell spatio-temporal response kinetics in severe neuroinflammatory disease
Publisher: Springer Science and Business Media LLC
Date: 26-07-2021
DOI: 10.1186/S12974-021-02214-Y
Abstract: Differentiating infiltrating myeloid cells from resident microglia in neuroinflammatory disease is challenging, because bone marrow-derived inflammatory monocytes infiltrating the inflamed brain adopt a ‘microglia-like’ phenotype. This precludes the accurate identification of either cell type without genetic manipulation, which is important to understand their temporal contribution to disease and inform effective intervention in its pathogenesis. During West Nile virus (WNV) encephalitis, widespread neuronal infection drives substantial CNS infiltration of inflammatory monocytes, causing severe immunopathology and/or death, but the role of microglia in this remains unclear. Using high-parameter cytometry and dimensionality-reduction, we devised a simple, novel gating strategy to identify microglia and infiltrating myeloid cells during WNV-infection. Validating our strategy, we (1) blocked the entry of infiltrating myeloid populations from peripheral blood using monoclonal blocking antibodies, (2) adoptively transferred BM-derived monocytes and tracked their phenotypic changes after infiltration and (3) labelled peripheral leukocytes that infiltrate into the brain with an intravenous dye. We demonstrated that myeloid immigrants populated only the identified macrophage gates, while PLX5622 depletion reduced all 4 subsets defined by the microglial gates. Using this gating approach, we identified four consistent microglia subsets in the homeostatic and WNV-infected brain. These were P2RY12 hi CD86 − , P2RY12 hi CD86 + and P2RY12 lo CD86 − P2RY12 lo CD86 + . During infection, 2 further populations were identified as 'inflammatory' and 'microglia-like' macrophages, recruited from the bone marrow. Detailed kinetic analysis showed significant increases in the proportions of both P2RY12 lo microglia subsets in all anatomical areas, largely at the expense of the P2RY12 hi CD86 − subset, with the latter undergoing compensatory proliferation, suggesting replenishment of, and differentiation from this subset in response to infection. Microglia altered their morphology early in infection, with all cells adopting temporal and regional disease-specific phenotypes. Late in disease, microglia produced IL-12, downregulated CX3CR1, F4/80 and TMEM119 and underwent apoptosis. Infiltrating macrophages expressed both TMEM119 and P2RY12 de novo, with the microglia-like subset notably exhibiting the highest proportional myeloid population death. Our approach enables detailed kinetic analysis of resident vs infiltrating myeloid cells in a wide range of neuroinflammatory models without non-physiological manipulation. This will more clearly inform potential therapeutic approaches that specifically modulate these cells.
Zika virus encephalitis in immunocompetent mice is dominated by innate immune cells and does not require T or B cells
Publisher: Springer Science and Business Media LLC
Date: 11-09-2019
DOI: 10.1186/S12974-019-1566-5
Abstract: Until the end of the twentieth century, Zika virus (ZIKV) was thought to cause a mostly mild, self-limiting disease in humans. However, as the geographic distribution of ZIKV has shifted, so too has its pathogenicity. Modern-day ZIKV infection is now known to cause encephalitis, acute disseminated encephalomyelitis, and Guillain-Barré syndrome in otherwise healthy adults. Nevertheless, the underlying pathogenetic mechanisms responsible for this shift in virulence remain unclear. Here, we investigated the contribution of the innate versus the adaptive immune response using a new mouse model involving intracranial infection of adult immunocompetent mice with a moderately low dose of ZIKV MR766. To determine the contribution of type I interferons (IFN-Is) and adaptive immune cells, we also studied mice deficient for the IFN-I receptor 1 ( Ifnar1 −/− ) and recombination-activating gene 1 ( Rag1 −/− ). We show that intracranial infection with ZIKV resulted in lethal encephalitis. In wild-type mice, ZIKV remained restricted predominantly to the central nervous system (CNS) and infected neurons, whereas astrocytes and microglia were spared. Histological and molecular analysis revealed prominent activation of resident microglia and infiltrating monocytes that were accompanied by an expression of pro-inflammatory cytokines. The disease was independent of T and B cells. Importantly, unlike peripheral infection, IFN-Is modulated but did not protect from infection and lethal disease. Lack of IFN-I signaling resulted in spread of the virus, generalized inflammatory changes, and accelerated disease onset. Using intracranial infection of immunocompetent wild-type mice with ZIKV, we demonstrate that in contrast to the peripheral immune system, the CNS is susceptible to infection and responds to ZIKV by initiating an antiviral immune response. This response is dominated by resident microglia and infiltrating monocytes and macrophages but does not require T or B cells. Unlike in the periphery, IFN-Is in the CNS cannot prevent the establishment of infection. Our findings show that ZIKV encephalitis in mice is dependent on the innate immune response, and adaptive immune cells play at most a minor role in disease pathogenesis.
TrackSOM: Mapping immune response dynamics through clustering of time‐course cytometry data
Publisher: Wiley
Date: 19-07-2023
DOI: 10.1002/CYTO.A.24668
Abstract: Mapping the dynamics of immune cell populations over time or disease‐course is key to understanding immunopathogenesis and devising putative interventions. We present TrackSOM, a novel method for delineating cellular populations and tracking their development over a time‐ or disease‐course cytometry datasets. We demonstrate TrackSOM‐enabled elucidation of the immune response to West Nile Virus infection in mice, uncovering heterogeneous subpopulations of immune cells and relating their functional evolution to disease severity. TrackSOM is easy to use, encompasses few parameters, is quick to execute, and enables an integrative and dynamic overview of the immune system kinetics that underlie disease progression and/or resolution.
Development of the activated high resolution 1H MR spectrum in murine T cells and B cells occurs in G1 phase of the cell cycle.
Publisher: Wiley
Date: 10-1990
Abstract: T and B lymphocytes stimulated with mitogens develop 1H MR spectra characteristic of triglycerides in an isotropic environment. These distinctive signals, which are also observed in malignant cells, cannot be suppressed by compounds which inhibit progression through the cell cycle. Cellular proliferation is thus not essential for the development and maintenance of high resolution lipid spectra in activated cells.
Early Induction of Interferon-Independent Virus-Specific ICAM-1 (CD54) Expression by Flavivirus in Quiescent but Not Proliferating Fibroblasts- Implications for Virus-Host Interactions
Publisher: Elsevier BV
Date: 04-1995
Abstract: West Nile Virus (WNV) infection of human embryonic fibroblasts can induce expression of ICAM-1 by two distinct mechanisms. An early and direct mechanism occurs within 2 hr of virus infection which is cytokine independent, and an indirect mechanism occurs within 24 hr of virus infection and is regulated by the release of IFN-type 1. Virus-inactivated, conditioned supernatants removed from WNV-infected fibroblast cultures at 4 hr did not alter ICAM-1 expression on fresh, untreated fibroblasts, whereas conditioned supernatants from 24-hr-infected cultures induced small increases in ICAM-1 expression after incubation for 24 hr but not after 4 hr. These studies also demonstrate that the expression of ICAM-1 on fibroblasts in response to flavivirus is cell-cycle dependent. WNV can only induce increased ICAM-1 expression in quiescent fibroblasts in G0 phase. In contrast, induction of ICAM-1 after exposure to types 1 and 2 IFN is not cell-cycle dependent. Other viruses, including double-stranded DNA viruses, vaccinia, and adenovirus 2 and 5 and the single, positive-stranded RNA alphavirus, Semiliki Forest virus, did not induce ICAM-1 expression on fibroblasts after 24 hr. Another alphavirus, Ross river, was able to induce ICAM-1 but only by the indirect mechanism of type 1 IFN-dependent release. The closely related flavivirus, Kunjin, induced increased ICAM-1 expression in a manner similar to WNV. The ability of flaviviruses to induce increased ICAM-1 expression directly within a few hours of infection may be an important virus-host survival strategy promoting cell-cell adhesion and hence possible further viral infection/replication.
Immuno-gold labeling for flow cytometric analysis
Publisher: Elsevier BV
Date: 11-1984
DOI: 10.1016/0022-1759(84)90366-1
Abstract: Colloidal gold particles coated with goat anti-mouse immunoglobulin antibodies were used to analyse surface antigens on various cell types by flow cytometry. The gold-labeled cells showed an increasing signal lification in the 90 degree light scatter with increasing wavelength of the incident laser light, reaching a more than 10-fold lification at 632.8 nm. This wavelength was provided by a 0.5 mW helium-neon laser. The magnitude of the signal lification due to the gold label as well as the specificity of the label was sufficient for quantitative discrimination between positive and negative cells. Cell viability was not affected by the gold label. Mouse spleen cells were labeled with various combinations of FITC- and gold-conjugated antibodies. It was found that the gold and fluorescent labels did not interfere with each other. Colloidal gold may thus be used as an additional label for multiparameter cell analysis and sorting. Biparametric cell analysis/sorting of surface antigen-labeled cells (label versus low-angle scatter) becomes possible even with a low energy helium-neon laser.
Clodronate is not protective in lethal viral encephalitis despite substantially reducing inflammatory monocyte infiltration in the CNS
Publisher: Frontiers Media SA
Date: 20-07-2023
DOI: 10.3389/FIMMU.2023.1203561
Abstract: Bone marrow (BM)-derived monocytes induce inflammation and tissue damage in a range of pathologies. In particular, in a mouse model of West Nile virus (WNV) encephalitis (WNE), nitric oxide-producing, Ly6C hi inflammatory monocytes from the BM are recruited to the central nervous system (CNS) and contribute to lethal immune pathology. Reducing the migration of these cells into the CNS using monoclonal antibody blockade, immune-modifying particles or CSF-1R inhibitors reduces neuroinflammation, improving survival and/or clinical outcomes. Macrophages can also be targeted more broadly by administration of clodronate-encapsulated liposomes, which induce apoptosis in phagocytes. In this study, clodronate reduced the inflammatory infiltrate by 70% in WNE, however, surprisingly, this had no effect on disease outcome. More detailed analysis demonstrated a compensatory increase in neutrophils and enhanced activation status of microglia in the brain. In addition, we observed increased numbers of Ly6C hi BM monocytes with an increased proliferative capacity and expression of SCA-1 and CD16/32, potentially indicating output of immature cells from the BM. Once in the brain, these cells were more phagocytic and had a reduced expression of antigen-presenting molecules. Lastly, we show that clodronate also reduces non-myeloid cells in the spleen and BM, as well as ablating red blood cells and their proliferation. These factors likely impeded the therapeutic potential of clodronate in WNE. Thus, while clodronate provides an excellent system to deplete macrophages in the body, it has larger and broader effects on the phagocytic and non-phagocytic system, which must be considered in the interpretation of data.
Triamcinolone acetonide modulates permeability and intercellular adhesion molecule-1 (ICAM-1) expression of the ECV304 cell line: Implications for macular degeneration
Publisher: Oxford University Press (OUP)
Date: 09-2000
DOI: 10.1046/J.1365-2249.2000.01316.X
Abstract: Whilst animal studies and a pilot clinical trial suggest that intravitreal triamcinolone acetonide (TA) may be useful in the treatment of age-related macular degeneration (AMD), its mode of action remains to be fully elucidated. The present study has investigated the capacity of TA to modulate the expression of adhesion molecules and permeability using a human epithelial cell line (ECV304) as a model of the outer blood–retinal barrier (BRB). The influence of TA on the expression of ICAM-1 and MHC-I was studied on resting and phorbol myristate acetate (PMA)- or interferon-gamma (IFN-γ)- and/or tumour necrosis factor-alpha (TNF-α)-activated cells using flow cytometry and immunocytochemistry. Additionally, ECV304 cells were grown to confluence in uncoated Transwell chambers transepithelial resistance (TER) across resting and PMA-activated cells was monitored. TA significantly decreased the paracellular permeability of ECV304 cells and down-regulated ICAM-1 expression, consistent with immunocytochemical observations. PMA-induced permeability changes were dose-dependent and TA decreased permeability of both resting and PMA-activated monolayers. MHC-I expression by ECV304 cells however, was not significantly affected by TA treatment. The modulation of TER and ICAM-1 expression in vitro correlate with clinical observations, suggesting re-establishment of the BRB and down-regulation of inflammatory markers are the principal effects of intravitreal TA in vivo. The results further indicate that TA has the potential to influence cellular permeability, including the barrier function of the retinal pigment epithelium (RPE) in AMD-affected retinae.
Ly6c+ inflammatory monocytes are microglial precursors recruited in a pathogenic manner in West Nile virus encephalitis
Publisher: Rockefeller University Press
Date: 08-09-2008
DOI: 10.1084/JEM.20080421
Abstract: In a lethal West Nile virus (WNV) model, central nervous system infection triggered a threefold increase in CD45int/CD11b+/CD11c− microglia at days 6–7 postinfection (p.i.). Few microglia were proliferating, suggesting that the increased numbers were derived from a migratory precursor cell. Depletion of “circulating” (Gr1−(Ly6Clo)CX3CR1+) and “inflammatory” (Gr1hi/Ly6Chi/CCR2+) classical monocytes during infection abrogated the increase in microglia. C57BL/6 chimeras reconstituted with cFMS–enhanced green fluorescent protein (EGFP) bone marrow (BM) showed large numbers of peripherally derived (GFP+) microglia expressing GR1+(Ly6C+) at day 7 p.i., suggesting that the inflammatory monocyte is a microglial precursor. This was confirmed by adoptive transfer of labeled BM (Ly6Chi/CD115+) or circulating inflammatory monocytes that trafficked to the WNV-infected brain and expressed a microglial phenotype. CCL2 is a chemokine that is highly expressed during WNV infection and important in inflammatory monocyte trafficking. Neutralization of CCL2 not only reduced the number of GFP+ microglia in the brain during WNV infection but prolonged the life of infected animals. Therefore, CCL2-dependent inflammatory monocyte migration is critical for increases in microglia during WNV infection and may also play a pathogenic role during WNV encephalitis.
Detection of extended γ-ray emission around the Geminga pulsar with H.E.S.S.
Publisher: EDP Sciences
Date: 05-2023
A deep spectromorphological study of the γ-ray emission surrounding the young massive stellar cluster Westerlund 1
Publisher: EDP Sciences
Date: 10-2022
DOI: 10.1051/0004-6361/202244323
Abstract: Context. Young massive stellar clusters are extreme environments and potentially provide the means for efficient particle acceleration. Indeed, they are increasingly considered as being responsible for a significant fraction of cosmic rays (CRs) that are accelerated within the Milky Way. Westerlund 1, the most massive known young stellar cluster in our Galaxy, is a prime candidate for studying this hypothesis. While the very-high-energy γ -ray source HESS J1646−458 has been detected in the vicinity of Westerlund 1 in the past, its association could not be firmly identified. Aims. We aim to identify the physical processes responsible for the γ -ray emission around Westerlund 1 and thus to understand the role of massive stellar clusters in the acceleration of Galactic CRs better. Methods. Using 164 h of data recorded with the High Energy Stereoscopic System (H.E.S.S.), we carried out a deep spectromorphological study of the γ -ray emission of HESS J1646−458. We furthermore employed H I and CO observations of the region to infer the presence of gas that could serve as target material for interactions of accelerated CRs. Results. We detected large-scale (∼2° diameter) γ -ray emission with a complex morphology, exhibiting a shell-like structure and showing no significant variation with γ -ray energy. The combined energy spectrum of the emission extends to several tens of TeV, and it is uniform across the entire source region. We did not find a clear correlation of the γ -ray emission with gas clouds as identified through H I and CO observations. Conclusions. We conclude that, of the known objects within the region, only Westerlund 1 can explain the majority of the γ -ray emission. Several CR acceleration sites and mechanisms are conceivable and discussed in detail. While it seems clear that Westerlund 1 acts as a powerful particle accelerator, no firm conclusions on the contribution of massive stellar clusters to the flux of Galactic CRs in general can be drawn at this point.
Inflammatory monocytes and the pathogenesis of viral encephalitis
Publisher: Springer Science and Business Media LLC
Date: 12-2012
Abstract: Monocytes are a heterogeneous population of bone marrow-derived cells that are recruited to sites of infection and inflammation in many models of human diseases, including those of the central nervous system (CNS). Ly6C hi /CCR2 hi inflammatory monocytes have been identified as the circulating precursors of brain macrophages, dendritic cells and arguably microglia in experimental autoimmune encephalomyelitis Alzheimer’s disease stroke and more recently in CNS infection caused by Herpes simplex virus, murine hepatitis virus, Theiler’s murine encephalomyelitis virus, Japanese encephalitis virus and West Nile virus. The precise differentiation pathways and functions of inflammatory monocyte-derived populations in the inflamed CNS remains a contentious issue, especially in regard to the existence of monocyte-derived microglia. Furthermore, the contributions of monocyte-derived subsets to viral clearance and immunopathology are not well-defined. Thus, understanding the pathways through which inflammatory monocytes migrate to the brain and their functional capacity within the CNS is critical to inform future therapeutic strategies. This review discusses some of the key aspects of inflammatory monocyte trafficking to the brain and addresses the role of these cells in viral encephalitis.
Quantitation of H-2 antigen expression on hepatocytes and macrophages: Evidence for an influence by strain background
Publisher: Wiley
Date: 12-1982
DOI: 10.1038/ICB.1982.67
Abstract: The surface concentration of H-2 complex antigens was measured by a quantitative immunoferritin labelling technique on hepatocytes and macrophages from five mouse strains with three haplotypes. The concentration of H-2 molecules was similar on macrophages from three B10 congenic strains, and the same similarity was observed on hepatocytes from the three strains. With both hepatocytes and macrophages, however, the surface concentration of H-2d molecules on BALB/c cells was about twice that on B10.D2 cells, and that of H-2k molecules on C3H/HeJ cells was about twice what we observed on B10.BR/SgSn cells. These measurements suggest a regulation of the surface concentration of H-2 complex antigens by a locus outside the MHC.
Role of IFN-γ in an experimental murine model of West Nile virus-induced seizures
Publisher: Wiley
Date: 03-07-2007
DOI: 10.1111/J.1471-4159.2007.04798.X
Abstract: Seizures are a major complication of viral encephalitis. However, the mechanisms of seizure-associated neuronal dysfunction remain poorly understood. We report that intranasal inoculation with West Nile virus (WNV) (Sarafend) causes limbic seizures in C57BL/6 mice, but not in interferon (IFN)-gamma-deficient (IFN-gamma-/-) mice. Both strains showed similar levels of virus in the brain, as well as similar concentrations of the cytokines, tumor necrosis factor and interleukin-6, both of which can alter neuronal excitability. Experiments in chimeric IFN-gamma-/- mice reconstituted with IFN-gamma-producing leukocytes showed that IFN-gamma is not required during central nervous system infection for limbic seizure development, suggesting a role for IFN-gamma in the developing brain. This was supported responses to pentylenetetrazole, kainic acid (KA), and N-methyl-d-aspartate (NMDA). Both strains of mice exhibited similar behavior after pentylenetetrazole challenge. However, while NMDA and KA treatment resulted in characteristic seizures in C57BL/6 mice, these responses were diminished (NMDA treatment) or absent (KA treatment) in IFN-gamma-/- mice. Furthermore, NMDA-receptor blockade with MK-801 in WNV-infected C57BL/6 mice abrogated seizures and prolonged survival. Our data show that IFN-gamma plays an important role in the development of the excitatory seizure pathways in the brain and that these cascades become pathogenic in encephalitic WNV infection.
Interleukin-1β But Not Tumor Necrosis Factor is Involved in West Nile Virus-Induced Langerhans Cell Migration from the Skin in C57BL/6 Mice
Publisher: Elsevier BV
Date: 09-2001
DOI: 10.1046/J.0022-202X.2001.01454.X
Abstract: Langerhans cells are bone marrow-derived epidermal dendritic cells. They migrate out of the epidermis into the lymphatics and travel to the draining lymph nodes where they are responsible for the activation of T cells in the primary immune response. Tumor necrosis factor and interleukin-1beta, have previously been shown to be responsible for Langerhans cell migration in response to contact sensitizers in BALB/C mice however, which cytokines are responsible for mediating Langerhans cell migration in response to a replicating cutaneously acquired virus such as the West Nile Virus, are not known. We have devised a method for identifying Langerhans cells in the draining lymph nodes using E-cadherin labeling and flow cytometry. We infected tumor necrosis factor-deficient gene knockout mice (tumor necrosis factor-/-) intradermally with West Nile Virus and found that levels of Langerhans cell emigration and accumulation in the draining lymph nodes were similar to wild-type C57BL/6 mice. This was borne out by the finding that high levels of systemic neutralizing anti-tumor necrosis factor antibody failed to inhibit the migration of Langerhans cells from the epidermis and their accumulation in the draining lymph nodes in wild-type C57BL/6 mice. In West Nile Virus-infected, tumor necrosis factor-/- mice treated with systemic neutralizing anti-interleukin-1beta antibodies, however, migration of Langerhans cells from the epidermis and their accumulation in the draining lymph nodes were significantly inhibited compared with control antibody-treated, infected animals. The results indicate that Langerhans cell migration, accumulation in the draining lymph nodes and the initiation of lymph node shut-down in response to a cutaneous West Nile Virus infection is dependent on interleukin-1beta and can occur in the absence of tumor necrosis factor.
Interaction of flaviviruses with cells of the vertebrate host and decoy of the immune response
Publisher: Wiley
Date: 06-2003
DOI: 10.1046/J.1440-1711.2003.01167.X
Abstract: Flaviviruses cause endemic and epidemic disease with significant morbidity and mortality throughout the world. In contrast to viruses that avoid the host immune response by down-regulating cell surface major histocompatibility complex expression, infection by members of the neurotropic Japanese encephalitis serogroup induce virus-directed functional increases in expression of class I and II major histocompatibility complex and various adhesion molecules, resulting in increased susceptibility to both virus- and major histocompatibility complex-specific cytotoxic T lymphocyte lysis. These changes are comodulated by T1 and T2 cytokines, as well as by cell cycle position and adherence status at infection. Infected skin dendritic (Langerhans) cells also show increased costimulatory molecule expression and local interleukin-1beta production causes accelerated migration of Langerhans cells to local draining lymph nodes, where initiation of antiviral immune responses occur. The exact mechanism(s) of up-regulation is unclear, but changes are associated with NF-kappaB activation and increased MHC and ICAM-1 gene transcription, independently of interferon or other pro-inflammatory cytokines. We hypothesize that these viruses may decoy the adaptive immune system into generating low-affinity, self-reactive T cells which clear virus poorly, as part of their survival strategy. This may enable viral growth and immune escape in cycling cells, which do not significantly up-regulate cell surface molecules. A possible side-effect of this might be immunopathology, caused by 'autoimmune' cross-reactive damage of uninfected high major histocompatibility complex and adhesion molecule-expressing cells, with consequent exacerbation of encephalitic disease. Results from a murine model of flavivirus encephalitis developed in this laboratory further suggest that interferon-gamma plays a crucial role in fatal immunopathology.
IL-22 and non-ELR-CXC chemokine expression in chronic hepatitis B virus-infected liver.
Publisher: Wiley
Date: 27-09-2012
DOI: 10.1038/ICB.2011.79
Abstract: Hepatitis B virus infection is still a major global health problem, despite decades of research. Interleukin (IL)-22 induces acute phase reactants and chemokines, favors anti-microbial defence and protects tissues from damage. IL-22 is important in chronic skin inflammation, but its role in chronic hepatitis B (CHB) is unclear. This study explores the association between intra-hepatic IL-22 expression, its relevant associated cytokines and the severity of liver inflammation/fibrosis in CHB patients. IL-22, IL-17, IL-10, IL-6, non-ELR-CXC chemokines (CXCL-9, CXCL-10, CXCL-11), fibroblast growth factors and Kupffer cell (KC) numbers were measured in patients with CHB (n=65), acute hepatitis B (AHB n=4), chronic hepatitis C (CHC n=14) and non-viral hepatitis (n=23), using immunohistochemistry. Expression of IL-22, IL-17, IL-10, IL-6, non-ELR-CXC chemokines and number of KCs in liver tissues were substantially higher in AHB patients than others. In CHB patients, the expression of IL-22, IL-6, CXCL-9 and CXCL-10 were significantly higher with alanine aminotransferase (ALT) levels ≤ twice the upper limit of normal (ULN), compared with those with ALT levels >twice the ULN, whereas IL-10 and IL-17 showed a reverse pattern. IL-22 was inversely (P<0.01), but IL-17 was positively (P<0.05), correlated with the histological activity index) in these patients, and a significant negative correlation between the fibrosis stage and IL-22 or non-ELR-CXC chemokines was observed. Furthermore, immunofluorescent labeling demonstrated a close spatial association of IL-22, CXCL-9, -10 or -11 in the CHB liver. We speculate that IL-22 and non-ELR-CXC chemokines synergistically may provide protection in liver inflammation/fibrosis during CHB infection.
H.E.S.S. and MAGIC observations of a sudden cessation of a very-high-energy γ-ray flare in PKS 1510−089 in May 2016
Publisher: EDP Sciences
Date: 04-2021
DOI: 10.1051/0004-6361/202038949
Abstract: The flat spectrum radio quasar (FSRQ) PKS 1510−089 is known for its complex multiwavelength behaviour and it is one of only a few FSRQs detected in very-high-energy (VHE, E 100 GeV) γ rays. The VHE γ -ray observations with H.E.S.S. and MAGIC in late May and early June 2016 resulted in the detection of an unprecedented flare, which revealed, for the first time, VHE γ -ray intranight variability for this source. While a common variability timescale of 1.5 h has been found, there is a significant deviation near the end of the flare, with a timescale of ∼20 min marking the cessation of the event. The peak flux is nearly two orders of magnitude above the low-level emission. For the first time, a curvature was detected in the VHE γ -ray spectrum of PKS 1510–089, which can be fully explained by the absorption on the part of the extragalactic background light. Optical R -band observations with ATOM revealed a counterpart of the γ -ray flare, even though the detailed flux evolution differs from the VHE γ -ray light curve. Interestingly, a steep flux decrease was observed at the same time as the cessation of the VHE γ -ray flare. In the high-energy (HE, E 100 MeV) γ -ray band, only a moderate flux increase was observed with Fermi -LAT, while the HE γ -ray spectrum significantly hardens up to a photon index of 1.6. A search for broad-line region (BLR) absorption features in the γ -ray spectrum indicates that the emission region is located outside of the BLR. Radio very-long-baseline interferometry observations reveal a fast-moving knot interacting with a standing jet feature around the time of the flare. As the standing feature is located ∼50 pc from the black hole, the emission region of the flare may have been located at a significant distance from the black hole. If this is indeed a true correlation, the VHE γ rays must have been produced far down in the jet, where turbulent plasma crosses a standing shock.
Human immunodeficiency virus type 1 infection of human placental macrophages in vitro.
Publisher: Oxford University Press (OUP)
Date: 09-1993
Abstract: Placental macrophages (Hofbauer cells) were isolated and cultured in vitro to investigate their susceptibility to human immunodeficiency virus type 1 (HIV-1) infection. Of adherent cells, 80% expressed CD14, and > 99% were nonspecific esterase-positive. CD4 antigen was expressed at very low levels. CD4 mRNA could be detected in the cells by reverse transcription followed by polymerase chain reaction. The macrophages were infected productively after inoculation with low-passage blood isolates of cell-free HIV-1. Peak virus titers were detected 3-7 days after infection by HIV-1 antigen ELISA and reverse transcriptase assay. Replication of HIV-1 in placental macrophages was less than in blood monocytes. HIV-1 RNA was detected in placental macrophages by in situ hybridization 16 days after infection. Multinucleated giant cells were identified in some cultures, indicative of an HIV-induced cytopathic effect. Thus, placental macrophages can be infected productively with clinical isolates of HIV-1, and such cells may act as a reservoir of virus for transmission to the fetus in utero.
Accelerated dendritic cell differentiation from migrating Ly6Clo bone marrow monocytes in early dermal West Nile virus infection
Publisher: The American Association of Immunologists
Date: 15-02-2011
Abstract: No study has investigated the participation of Ly6C+ monocytes in the earliest phase of skin infection with the mosquito-borne West Nile virus. In a novel murine model mimicking natural dermal infection, CCL2-dependent bone marrow (BM)-derived monocyte migration, differentiation into Ly6C+ dendritic cells (DC), and accumulation around dermal deposits of infected fibroblasts by day 1 postinfection were associated with increasing numbers of monocyte-derived TNF/inducible NO synthase-producing DC by day 2 postinfection in draining auricular lymph nodes (ALN). Adoptive transfer demonstrated simultaneous migration of bone marrow-derived Ly6Clo monocytes to virus-infected dermis and ALN, where they first become Ly6Chi DC within 24 h and then Ly6Clo DC by 72 h. DC migration from the infected dermis to the ALN derived exclusively from Ly6Clo BM monocytes. This demonstrates that Ly6Chi and Ly6Clo BM-derived monocytes have different fates in vivo and suggests that BM may be a reservoir of preinflammatory monocytes for rapid deployment as inflammatory DC during virus infection.
Contagious: Cultures, Carriers, and the Outbreak Narrative (review)
Publisher: Project MUSE
Date: 2010
DOI: 10.1353/BHM.0.0319
Can live-attenuated SARS-CoV-2 vaccine contribute to stopping the pandemic?
Publisher: Public Library of Science (PLoS)
Date: 21-09-2022
Microbial Infection as a Trigger of T-Cell Autoimmunity
Publisher: Elsevier
Date: 2020
Rational surface design of upconversion nanoparticles with polyethylenimine (PEI) coating for biomedical applications
Publisher: American Chemical Society (ACS)
Date: 08-08-2018
Flavivirus infection induces indoleamine 2,3-dioxygenase in human monocyte-derived macrophages via tumor necrosis factor and NF-κB
Publisher: Oxford University Press (OUP)
Date: 04-2012
DOI: 10.1189/JLB.1011532
Abstract: Infection with West Nile virus (WNV) via a mosquito bite results in local viral replication in the skin, followed by viremia. Thus, tissue macrophages are ideally located to prevent the dissemination of WNV throughout the host. The current study shows that WNV infection of human monocyte-derived macrophages (MDM) results in increased WNV mRNA, protein, and infectious virions at 24 h p.i. with a decline in titer after 48 h. Concomitant with viral control was the robust induction of indoleamine 2,3-dioxygenase (IDO) and resultant metabolism of L-tryptophan (L-Trp) to kynurenine. In WNV-exposed cultures, IDO protein was induced primarily in noninfected versus viral-infected MDM. Whereas WNV infection increased the production of IFN-α, IFN-β, and TNF, only antibody neutralization of TNF attenuated IDO expression and activity. WNV infection also activated NF-κB, and inhibition of this pathway with BMS-345541 abrogated IDO induction. Similar results were also obtained with MDM infected with the related flavivirus, Japanese encephalitis virus. Whereas IDO-mediated L-Trp metabolism can exhibit antiviral properties, inhibition of IDO activity in MDM with L-1-MT or the addition of excess L-Trp did not affect viral control. However, culturing MDM in L-Trp-deficient medium or overexpression of IDO in cells prior to infection significantly attenuated WNV replication, which was reversed by adding excess L-Trp. Together, these data support that although IDO is not required by MDM for the clearance of established viral infection, the spread of flavivirus infection is limited by IDO expressed in uninfected, neighboring cells.
Routes of inoculation and the immune response to a resolving genital flavivirus infection in a novel murine model
Publisher: Wiley
Date: 04-2004
Regulation of antigen processing and presentation molecules in West Nile virus-infected human skin fibroblasts
Publisher: Elsevier BV
Date: 07-2004
Analysis of the Murine Bone Marrow Hematopoietic System Using Mass and Flow Cytometry.
Publisher: Springer New York
Date: 2019
DOI: 10.1007/978-1-4939-9454-0_12
Abstract: The hematopoietic system produces erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets) throughout the life of an organism. Long-lived hematopoietic stem cells give rise to early progenitors with multi-lineage potential that progressively differentiate into lineage-specific progenitors. Following lineage commitment, these progenitors proliferate and expand, before eventually differentiating into their mature forms. This process drives the up- and downregulation of a wide variety of surface and intracellular markers throughout differentiation, making cytometric analysis of this interconnected system challenging. Moreover, during inflammation, the hematopoietic system can be mobilized to re-prioritize the production of various lineages, in order to match increased demand, often at the expense of other lineages. As such, the response of the hematopoietic system in the bone marrow (BM) is a critical component of both immunity and disease. Because of the complexity of the hematopoietic system in steady state and disease, high-dimensional cytometry technologies are well suited to the exploration of these complex systems. Here we describe a protocol for the extraction of murine bone marrow, and preparation for examination using high-dimensional flow or mass cytometry. Additionally, we describe methods for performing cell cycle assays using bromodeoxyuridine (BrdU) or iododeoxyuridine (IdU). Finally, we describe an analytical method that allows for a system-level analysis of the hematopoietic system in steady state or inflammatory scenarios.
Experimental severe malaria is resolved by targeting newly-identified monocyte subsets using immune-modifying particles combined with artesunate
Publisher: Springer Science and Business Media LLC
Date: 13-12-2018
DOI: 10.1038/S42003-018-0216-2
Abstract: Current treatment of severe malaria and associated cerebral malaria (CM) and respiratory distress syndromes are directed primarily at the parasite. Targeting the parasite has only partial efficacy in advanced infection, as neurological damage and respiratory distress are due to accumulation of host blood cells in the brain microvasculature and lung interstitium. Here, computational analysis identifies Ly6C lo monocytes as a major component of the immune infiltrate in both organs in a preclinical mouse model. Specifically targeting Ly6C lo monocyte precursors, identified by adoptive transfer, with immune-modifying particles (IMP) prevents experimental CM (ECM) in 50% of Plasmodium berghei ANKA-infected mice in early treatment protocols. Furthermore, treatment at onset of clinical ECM with 2 doses of a novel combination of IMP and anti-malarial drug artesunate results in 88% survival. This combination confers protection against ECM and mortality in late stage severe experimental malaria and provides a viable advance on current treatment regimens.
HIV infection of placental macrophages: Their potential role in vertical transmission
Publisher: Oxford University Press (OUP)
Date: 09-1994
DOI: 10.1002/JLB.56.3.241
Abstract: Placental macrophages were isolated and cultured in vitro to investigate their susceptibility to HIV infection and possible role in vertical transmission of HIV. After 10 days of in vitro culture the cells were positive for nonspecific esterase and acid phosphatase and negative for myeloperoxidase and placental alkaline phosphatase. They expressed cell surface HLA-ABC, HLA-DR, CD45, as well as CD68 intracellularly, as detected by flow cytometry, confirming their macrophage lineage. Approximately 80% of cells expressed surface CD14. CD4 antigen was expressed at very low levels and was confirmed by antibody blocking experiments. Infection of placental macrophage cultures with HIV resulted in a transient peak of viral replication 3 to 7 days after infection, but no later rise in HIV was detected with culture of up to 60 days. HIV replication was not up-regulated by coculture with phytohemagglutinin-stimulated lymphocytes or by treating infected cultures with tumor necrosis factor α or granulocyte-macrophage colony-stimulating factor. J. Leukoc. Biol. 56: 241–246 1994.
Regulation of immune recognition molecules by flavivirus, West Nile
Publisher: Mary Ann Liebert Inc
Date: 06-2002
DOI: 10.1089/08828240260066224
Abstract: We have shown the flaviviruses can up-regulate the cell surface expression of the immune recognition molecules, major histocompatability complex class-I and class-II (MHC-I, MHC-II), ICAM-1, VCAM, and E-selectin, in an interferon-independent and tumor necrosis factor-independent manner. This up-regulation is associated with an increased transcription of the relevant genes and is due to activation of the transcription factor, nuclear factor-kappa B. The level of up-regulation is determined in part by the cell cycle position of the cell when infected with the flavivirus, as quiescent cells show a greater increase in the level of expression of the immune recognition molecules, MHC-I and ICAM-1, than cells in other phases of the cell cycle. The resultant increased cell surface expression is functional with the increased expression resulting in increased recognition by flavivirus-specific and allo-specific cytotoxic T cells.
Integrating transcriptomic datasets across neurological disease identifies unique myeloid subpopulations driving disease‐specific signatures
Publisher: Wiley
Date: 16-12-2022
DOI: 10.1002/GLIA.24314
Abstract: Microglia and bone marrow‐derived monocytes are key elements of central nervous system (CNS) inflammation, both capable of enhancing and d ening immune‐mediated pathology. However, the study‐specific focus on in idual cell types, disease models or experimental approaches has limited our ability to infer common and disease‐specific responses. This meta‐analysis integrates bulk and single‐cell transcriptomic datasets of microglia and monocytes from disease models of autoimmunity, neurodegeneration, sterile injury, and infection to build a comprehensive resource connecting myeloid responses across CNS disease. We demonstrate that the bulk microglial and monocyte program is highly contingent on the disease environment, challenging the notion of a universal microglial disease signature. Integration of six single‐cell RNA‐sequencing datasets revealed that these disease‐specific signatures are likely driven by differing proportions of unique myeloid subpopulations that were in idually expanded in different disease settings. These subsets were functionally‐defined as neurodegeneration‐associated, inflammatory, interferon‐responsive, phagocytic, antigen‐presenting, and lipopolysaccharide‐responsive cellular states, revealing a core set of myeloid responses at the single‐cell level that are conserved across CNS pathology. Showcasing the predictive and practical value of this resource, we performed differential expression analysis on microglia and monocytes across disease and identified Cd81 as a new neuroinflammatory‐stable gene that accurately identified microglia and distinguished them from monocyte‐derived cells across all experimental models at both the bulk and single‐cell level. Together, this resource dissects the influence of disease environment on shared immune response programmes to build a unified perspective of myeloid behavior across CNS pathology.
Evidence of 100 TeV γ-ray emission from HESS J1702-420: A new PeVatron candidate
Publisher: EDP Sciences
Date: 09-2021
DOI: 10.1051/0004-6361/202140962
Abstract: Aims. The identification of PeVatrons, hadronic particle accelerators reaching the knee of the cosmic ray spectrum (few × 10 15 eV), is crucial to understand the origin of cosmic rays in the Galaxy. We provide an update on the unidentified source HESS J1702-420, a promising PeVatron candidate. Methods. We present new observations of HESS J1702-420 made with the High Energy Stereoscopic System (H.E.S.S.), and processed using improved analysis techniques. The analysis configuration was optimized to enhance the collection area at the highest energies. We applied a three-dimensional likelihood analysis to model the source region and adjust non thermal radiative spectral models to the γ -ray data. We also analyzed archival Fermi Large Area Telescope data to constrain the source spectrum at γ -ray energies 10 GeV. Results. We report the detection of γ -rays up to 100 TeV from a specific region of HESS J1702-420, which is well described by a new source component called HESS J1702-420A that was separated from the bulk of TeV emission at a 5.4 σ confidence level. The power law γ -ray spectrum of HESS J1702-420A extends with an index of Γ = 1.53 ± 0.19 stat ± 0.20 sys and without curvature up to the energy band 64−113 TeV, in which it was detected by H.E.S.S. at a 4.0 σ confidence level. This makes HESS J1702-420A a compelling candidate site for the presence of extremely high energy cosmic rays. With a flux above 2 TeV of (2.08 ± 0.49 stat ± 0.62 sys ) × 10 −13 cm −2 s −1 and a radius of (0.06 ± 0.02 stat ± 0.03 sys )°, HESS J1702-420A is outshone – below a few tens of TeV – by the companion HESS J1702-420B. The latter has a steep spectral index of Γ = 2.62 ± 0.10 stat ± 0.20 sys and an elongated shape, and it accounts for most of the low-energy HESS J1702-420 flux. Simple hadronic and leptonic emission models can be well adjusted to the spectra of both components. Remarkably, in a hadronic scenario, the cut-off energy of the particle distribution powering HESS J1702-420A is found to be higher than 0.5 PeV at a 95% confidence level. Conclusions. For the first time, H.E.S.S. resolved two components with significantly different morphologies and spectral indices, both detected at 5 σ confidence level, whose combined emissions result in the source HESS J1702-420. We detected HESS J1702-420A at a 4.0 σ confidence level in the energy band 64−113 TeV, which brings evidence for the source emission up to 100 TeV. In a hadronic emission scenario, the hard γ -ray spectrum of HESS J1702-420A implies that the source likely harbors PeV protons, thus becoming one of the most solid PeVatron candidates detected so far in H.E.S.S. data. However, a leptonic origin of the observed TeV emission cannot be ruled out either.
Migration of Foreign Lymphocytes from the Mouse Vagina into the Cervicovaginal Mucosa and to the Iliac Lymph Nodes1
Publisher: Oxford University Press (OUP)
Date: 02-1997
DOI: 10.1095/BIOLREPROD56.2.537
Abstract: The mode of heterosexual transmission of human immunodeficiency virus (HIV) is not yet understood. The semen of HIV-infected men contains free virus and infected cells, and it is not known which of these is more important for sexual transmission of the virus to women. Some investigators have presented in vitro studies supporting a cellular mode of transmission of HIV and have suggested that infected lymphoid cells may act as the primary source of infection. This has become known as the "Trojan Horse" hypothesis. In vivo demonstrations of such events are lacking and are not likely to be forthcoming using human subjects. To investigate the ability of normal lymphoid cells to invade the cervicovaginal mucosa in an experimental animal, we stained C3H/He (H-2Kk) mouse peritoneal lymphoid cells with bisbenzimide, a vital fluorescent DNA-binding dye, and inoculated the cells atraumatically into the vaginas of progestin-treated, BALB/c (H-2Kd) recipient mice. Donor cells were identified in recipient tissues by their bisbenzimide-fluorescent nuclei and by fluorescein staining of the membrane antigen, H-2Kk. Donor lymphoid cells were observed in histological sections of recipient cervicovaginal mucosa and also in the iliac lymph nodes of 34 of 36 recipient mice 24 h after inoculation into the vagina. The number of donor cells in the iliac lymph nodes was 8.6 +/- 1.4 (mean +/- SEM) cells per mouse with a range of 0-35 cells per mouse. Approximately 28% of the donor lymphoid cells in recipient lymph nodes expressed CD4, which in humans is the receptor for HIV. We did not detect F4/80, a marker of mature mouse macrophages in the donor cell population, on any of the migrating cells in recipient lymph nodes. However, this negative result is equivocal, because the marker might be down-regulated after transfer or the migrating macrophages might be difficult to dissociate from the recipient lymph node tissue. These observations in mice support the suggestion that HIV-containing lymphoid cells in the semen of infected men may invade the cervicovaginal mucosa after sexual intercourse and deliver the virus to a woman's internal environment. However, both the donor cells and the recipient reproductive tract of the mice in the present study differed in significant respects from their counterparts in humans that might be involved in heterosexual HIV transmission. Further studies are needed to determine whether this possible mode of virus transmission is mainly responsible for heterosexual transmission of HIV in humans.
Major Histocompatibility Complex Class I (MHC-I) Induction by West Nile Virus: Involvement of 2 Signaling Pathways in MHC-I Up-Regulation
Publisher: Oxford University Press (OUP)
Date: 15-02-2004
DOI: 10.1086/381501
The intracellular oxidation of 2′,7′-dichlorofluorescin in murine T lymphocytes
Publisher: Elsevier BV
Date: 2001
DOI: 10.1016/S0891-5849(00)00449-4
Abstract: Intracellular reactive oxygen species (ROS) production by activated murine T lymphocytes was investigated by analyzing intracellular dichlorofluorescin (DCFH(2)) oxidation in lymph node cells (LNC). An increase in DCFH(2) oxidation in LNC induced by phorbol myristate acetate (PMA) was detected by flow cytometry. It was confirmed that this increase was present in Thy1(+) LNC. We examined the contribution to intracellular DCFH(2) oxidation of ROS released by leukocytes other than T cells present in the LNC suspension. Superoxide dismutase, catalase, and glutathione/glutathione peroxidase inhibited the PMA-induced increase in intracellular DCFH(2) oxidation. Furthermore, PMA failed to elicit DCFH(2) oxidation in LNC isolated from mice lacking a functional NADPH oxidase (gp91(phox) gene knockout mice), but this response could be restored in these cells by the addition of T cell-depleted LNC from wild-type litter mates. This study highlights the necessity for caution in using the DCFH(2) assay to demonstrate specific intracellular ROS production in heterogeneous cell populations. It also suggests that cells other than T cells in lymph node populations may, through production of ROS, influence the intracellular redox state of T lymphocytes.
A MeerKAT, e-MERLIN, H.E.S.S., and Swift search for persistent and transient emission associated with three localized FRBs
Publisher: Oxford University Press (OUP)
Date: 16-06-2022
Abstract: We report on a search for persistent radio emission from the one-off fast radio burst (FRB) 20190714A, as well as from two repeating FRBs, 20190711A and 20171019A, using the MeerKAT radio telescope. For FRB 20171019A, we also conducted simultaneous observations with the High-Energy Stereoscopic System (H.E.S.S.) in very high-energy gamma rays and searched for signals in the ultraviolet, optical, and X-ray bands. For this FRB, we obtain a UV flux upper limit of $1.39 \\times 10^{-16}~{\\rm erg\\, cm^{-2}\\, s^{-1}}$Å−1, X-ray limit of $\\sim 6.6 \\times 10^{-14}~{\\rm erg\\, cm^{-2}\\, s^{-1}}$ and a limit on the very high energy gamma-ray flux $\\Phi (E\\gt 120\\, {\\rm GeV}) \\lt 1.7\\times 10^{-12}\\, \\mathrm{erg\\, cm^{-2}\\, s^{-1}}$. We obtain a radio upper limit of ∼15 $\\mu$Jy beam−1 for persistent emission at the locations of both FRBs 20190711A and 20171019A with MeerKAT. However, we detected an almost unresolved (ratio of integrated flux to peak flux is ∼1.7 beam) radio emission, where the synthesized beam size was ∼ 8 arcsec size with a peak brightness of $\\sim 53\\, \\mu$Jy beam−1 at MeerKAT and $\\sim 86\\, \\mu$Jy beam−1 at e-MERLIN, possibly associated with FRB 20190714A at z = 0.2365. This represents the first detection of persistent continuum radio emission potentially associated with a (as-yet) non-repeating FRB. If the association is confirmed, one of the strongest remaining distinction between repeaters and non-repeaters would no longer be applicable. A parallel search for repeat bursts from these FRBs revealed no new detections down to a fluence of 0.08 Jy ms for a 1 ms duration burst.
Acellular organ scaffolds for tumor tissue engineering
Publisher: SPIE
Date: 22-12-2015
DOI: 10.1117/12.2202473
Putting PLX5622 into perspective: microglia in central nervous system viral infection
Publisher: Medknow
Date: 2023
Pretty in pink...
Publisher: Informa UK Limited
Date: 02-2000
Flavivirus encephalitis: Immunopathogenesis of disease and immunomodulation
Publisher: Springer New York
Date: 2015
The Delta SARS-CoV-2 Variant of Concern Induces Distinct Pathogenic Patterns of Respiratory Disease in K18-hACE2 Transgenic Mice Compared to the Ancestral Strain from Wuhan
Publisher: American Society for Microbiology
Date: 28-06-2022
Abstract: SARS-CoV-2 variants, with the threat of increased transmissibility, infectivity, and immune escape, continue to emerge as the COVID-19 pandemic progresses. Detailing the pathogenesis of disease caused by SARS-CoV-2 variants, such as Delta, is essential to better understand the clinical threat caused by emerging variants and associated disease.
Tolerance induced by apoptotic antigen-coupled leukocytes is induced by PD-L1+ and IL-10-producing splenic macrophages and maintained by T regulatory cells
Publisher: The American Association of Immunologists
Date: 09-2011
Abstract: Ag-specific tolerance is a highly desired therapy for immune-mediated diseases. Intravenous infusion of protein eptide Ags linked to syngeneic splenic leukocytes with ethylene carbodiimide (Ag-coupled splenocytes [Ag-SP]) has been demonstrated to be a highly efficient method for inducing peripheral, Ag-specific T cell tolerance for treatment of autoimmune disease. However, little is understood about the mechanisms underlying this therapy. In this study, we show that apoptotic Ag-SP accumulate in the splenic marginal zone, where their uptake by F4/80+ macrophages induces production of IL-10, which upregulates the expression of the immunomodulatory costimulatory molecule PD-L1 that is essential for Ag-SP tolerance induction. Ag-SP infusion also induces T regulatory cells that are dispensable for tolerance induction but required for long-term tolerance maintenance. Collectively, these results indicate that Ag-SP tolerance recapitulates how tolerance is normally maintained in the hematopoietic compartment and highlight the interplay between the innate and adaptive immune systems in the induction of Ag-SP tolerance. To our knowledge, we show for the first time that tolerance results from the synergistic effects of two distinct mechanisms, PD-L1–dependent T cell-intrinsic unresponsiveness and the activation of T regulatory cells. These findings are particularly relevant as this tolerance protocol is currently being tested in a Phase I/IIa clinical trial in new-onset relapsing-remitting multiple sclerosis.
Rhinovirus-Induced Exacerbations of Asthma
Publisher: American Thoracic Society
Date: 08-2010
Entry of herpes simplex virus type 1 (HSV-1) into the distal axons of trigeminal neurons favors the onset of nonproductive, silent infection
Publisher: Public Library of Science (PLoS)
Date: 10-05-2012
Regulation of cellular adhesion molecule expression in murine oocytes, peri-implantation and post-implantation embryos
Publisher: Springer Science and Business Media LLC
Date: 12-2002
Abstract: Expression of the adhesion molecules, ICAM-1, VCAM-1, NCAM, CD44, CD49d (VLA-4, alpha chain), and CD11a (LFA-1, alpha chain) on mouse oocytes, and pre- and peri-implantation stage embryos was examined by quantitative indirect immunofluorescence microscopy. ICAM-1 was most strongly expressed at the oocyte stage, gradually declining almost to undetectable levels by the expanded blastocyst stage. NCAM, also expressed maximally on the oocyte, declined to undetectable levels beyond the morula stage. On the other hand, CD44 declined from highest expression at the oocyte stage to show a second maximum at the compacted 8-cell/morula. This molecule exhibited high expression around contact areas between trophectoderm and zona pellucida during blastocyst hatching. CD49d was highly expressed in the oocyte, remained significantly expressed throughout and after blastocyst hatching was expressed on the polar trophectoderm. Like CD44, CD49d declined to undetectable levels at the blastocyst outgrowth stage. Expression of both VCAM-1 and CD11a was undetectable throughout. The diametrical temporal expression pattern of ICAM-1 and NCAM compared to CD44 and CD49d suggest that dynamic changes in expression of adhesion molecules may be important for interaction of the embryo with the maternal cellular environment as well as for continuing development and survival of the early embryo.
Ontogeny of major histocompatibility complex antigen expression on cultured human embryonic skeletal myoblasts
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-1994
DOI: 10.1097/00007890-199409150-00010
Abstract: Human embryonic myoblasts isolated from 13- to 19-week embryos were treated for 24 to 144 hr with 0.1-500 U/ml IFN-gamma and the constitutive and IFN-gamma-inducible MHC expression was examined by flow cytometry. Low levels of constitutive MHC I were expressed that increased with both developmental age and incubation time. In contrast, no constitutive MHC II was detected on human embryonic myoblasts at any age or incubation time. Both classes of MHC can be induced by IFN-gamma. Maximal MHC I induction increased in parallel with age, i.e., maximal induction occurred on 19-week myoblasts, while MHC II induction peaked at 17 weeks. IFN-gamma-induced expression of MHC I and II also increased with incubation time. Induced expression of MHC I antigen reached plateau levels at 72 hr of IFN-gamma incubation, whereas MHC II increased to a plateau level at 120 hr. The immunological importance of these findings for myoblast transfer therapy is discussed.
Enhanced viral clearance and reduced leukocyte infiltration in experimental herpes encephalitis after intranasal infection of CXCR3-deficient mice
Publisher: Springer Science and Business Media LLC
Date: 23-01-2017
DOI: 10.1007/S13365-016-0508-6
Abstract: Herpes simplex virus type 1 (HSV-1) encephalitis (HSE) is the most common fatal sporadic encephalitis in developed countries. There is evidence from HSE animal models that not only direct virus-mediated damage caused but also the host's immune response contributes to the high mortality of the disease. Chemokines modulate and orchestrate this immune response. Previous experimental studies in HSE models identified the chemokine receptor CXCR3 and its ligands as molecules with a high impact on the course of HSE in mouse models. In this study, the role of the chemokine receptor CXCR3 was evaluated after intranasal infection with the encephalitogenic HSV-1 strain 17 syn
Dimensionality Reduction for Clustering and Cluster Tracking of Cytometry Data
Publisher: Springer International Publishing
Date: 2019
Harnessing nanoparticles for immune modulation
Publisher: Elsevier BV
Date: 07-2015
Increased proinflammatory responses from asthmatic human airway smooth muscle cells in response to rhinovirus infection
Publisher: Springer Science and Business Media LLC
Date: 03-05-2006
The role of tumor necrosis factor in modulating responses of murine embryo fibroblasts by flavivirus, West Nile
Publisher: Elsevier BV
Date: 11-2004
DOI: 10.1016/J.VIROL.2004.06.050
Abstract: Murine embryo fibroblasts (MEF) transcribe tumor necrosis factor (TNF) mRNA and secrete soluble TNF in response to infection by West Nile virus (WNV) and TNF was demonstrated to be protective against WNV infection in vitro. TNF is not required for the WNV-induced upregulation of MHC-I expression on MEF, as TNF deficiency did not affect the upregulation of major histocompatibility complex class I (MHC-I) by WNV. Furthermore, NF-kappaB was activated by WNV in TNF-deficient MEF, demonstrating that WNV induces NF-kappaB activation in a TNF-independent manner. The subunits of NF-kappaB activated by TNF and WNV differed, WNV-activated a p65 50 NF-kappaB complex while TNF-activated NF-kappaB was composed of p65, p50, and c-Rel. Furthermore, TNF-induced activation of NF-kappaB occurred earlier than WNV-induced NF-kappaB activation. The data demonstrate that WNV infection of MEF is associated with TNF production, but the WNV-induced activation of NF-kappaB and subsequent upregulation of MHC-I by WNV is TNF-independent.
Evidence for γ-ray emission from the remnant of Kepler’s supernova based on deep H.E.S.S. observations
Publisher: EDP Sciences
Date: 06-2022
DOI: 10.1051/0004-6361/202243096
Abstract: Observations with imaging atmospheric Cherenkov telescopes (IACTs) have enhanced our knowledge of nearby supernova (SN) remnants with ages younger than 500 yr by establishing Cassiopeia A and the remnant of Tycho’s SN as very-high-energy (VHE) γ -ray sources. The remnant of Kepler’s SN, which is the product of the most recent naked-eye SN in our Galaxy, is comparable in age to the other two, but is significantly more distant. If the γ -ray luminosities of the remnants of Tycho’s and Kepler’s SNe are similar, then the latter is expected to be one of the faintest γ -ray sources within reach of the current generation IACT arrays. Here we report evidence at a statistical level of 4.6 σ for a VHE signal from the remnant of Kepler’s SN based on deep observations by the High Energy Stereoscopic System (H.E.S.S.) with an exposure of 152 h. The measured integral flux above an energy of 226 GeV is ∼0.3% of the flux of the Crab Nebula. The spectral energy distribution (SED) reveals a γ -ray emitting component connecting the VHE emission observed with H.E.S.S. to the emission observed at GeV energies with Fermi -LAT. The overall SED is similar to that of the remnant of Tycho’s SN, possibly indicating the same nonthermal emission processes acting in both these young remnants of thermonuclear SNe.
Enhanced antiviral antibody secretion and attenuated immunopathology during influenza virus infection in nitric oxide synthase-2-deficient mice
Publisher: Microbiology Society
Date: 11-2006
Abstract: NOS2 gene-deficient (NOS2 −/− ) mice are less susceptible than wild-type (NOS2 +/+ ) mice to infection with Influenza A virus . Virus titres in the lungs of influenza-infected NOS2 −/− mice are significantly lower than those in NOS2 +/+ mice, with enhanced viral clearance in NOS2 −/− mice dependent on gamma interferon (IFN- γ ). The current study was undertaken to ascertain the role of specific components of the immune response in promoting virus clearance in influenza-infected NOS2 −/− mice. Levels of T cell- and natural killer cell-mediated cytotoxicity in the lungs of virus-infected mice were not significantly different between NOS2 +/+ and NOS2 −/− mice. However, virus-infected NOS2 −/− mice produced higher levels of virus-specific IgG2a antibody. Furthermore, more viable B cells and plasmablasts, along with greater levels of IFN- γ , were found in NOS2 −/− splenocyte cultures stimulated with B-cell mitogens. In addition to the early reduction in virus titres, clinical symptoms and proinflammatory cytokine production were attenuated in NOS2 −/− mice. Thus, NOS2 −/− B cells are capable of responding rapidly to influenza virus infection by proliferating and preferentially producing antibody of the IgG2a subtype. The relationship between viral load and the development of immunopathology is discussed.
The role of CXCR3 in DSS-induced colitis
Publisher: Public Library of Science (PLoS)
Date: 03-07-2014
1H-NMR visible neutral lipids in activated T lymphocytes: Relationship to phosphatidylcholine cycling
Publisher: Elsevier BV
Date: 10-1996
DOI: 10.1016/0005-2760(96)00104-X
Abstract: Two-dimensional 1H-NMR spectroscopy was used to compare changes in the concentration of isotropically-tumbling neutral lipid during the activation of splenic and thymic T lymphocytes. The concentration of mobile neutral lipid (MNL) was similar in splenic and thymic T cells after 72 h of activation with phorbol myristate acetate and ionomycin. However, after 120 h of activation, MNL concentrations in splenic T cells were more than 3-fold higher than in thymic T cells. An increase in choline (Cho), phosphocholine (PCho) and glycerophosphocholine (GPC) was also observed in both thymic and splenic T cells after 24 h of activation. However, after 72 h of stimulation, Cho and PCho levels had decreased and continued to decline at 96-120 h, while GPC continued to be maintained at elevated levels. The simultaneous increase in MNL and GPC and the decline in Cho and PCho leads us to propose that the synthesis of NMR-visible MNL in activated lymphocytes is linked to the phosphatidylcholine cycle.
Molecules in focus: Indoleamine 2,3-dioxygenase
Publisher: Elsevier BV
Date: 2007
DOI: 10.1016/J.BIOCEL.2007.01.004
Abstract: Indoleamine 2,3-dioxygenase (IDO) is a heme enzyme that initiates the oxidative degradation of the least abundant, essential amino acid, l-tryptophan, along the kynurenine pathway. The local cellular depletion of l-tryptophan that results may enable the host to inhibit the growth of various infectious pathogens in vivo. However, over the past decade, it has become increasingly apparent that IDO also represents an important immune control enzyme. Thus, cells expressing IDO, seemingly paradoxically, are capable of suppressing local T cell responses to promote immune tolerance under various physiological and pathophysiological conditions of medical importance, including infectious diseases, foetal rejection, organ transplantation, neuropathology, inflammatory and auto-immune disorders and cancer. In this review, we briefly outline the biochemical properties of IDO, its known and hypothetical functions and the medical implications for inhibition or induction of IDO and/or its downstream catabolites in health and disease.
Rhinovirus infection induces expression of airway remodelling factors in vitro and in vivo
Publisher: Wiley
Date: 27-01-2011
DOI: 10.1111/J.1440-1843.2010.01918.X
Abstract: A hallmark of asthma is airway remodelling, which includes increased deposition of extracellular matrix (ECM) protein. Viral infections may promote the development of asthma and are the most common causes of asthma exacerbations. We evaluated whether rhinovirus (RV) infection induces airway remodelling, as assessed by ECM deposition. Primary human bronchial epithelial cells and lung parenchymal fibroblasts were infected with RV-2 or RV-16, or treated with RV-16 RNA, imiquimod (Toll-like receptor (TLR) 7/8 agonist) or polyinosinic : polycytidylic acid (poly I : C) (activator of TLR 3, retinoic-acid-inducible protein I and melanoma-differentiated-associated gene 5). Changes in ECM proteins and their transcription were measured by ELISA and quantitative real-time PCR. In addition, gene expression for ECM proteins was assessed in a mouse model of RV infection. RV infection increased deposition of the ECM protein, perlecan, by human bronchial epithelial cells, and collagen V and matrix-bound vascular endothelial growth factor were increased in both human bronchial epithelial cell and fibroblast cultures. Purified RV-16 RNA, poly I : C and imiquimod induced similar increases in ECM deposition to those observed with RV-infected fibroblasts. However, only poly I : C induced ECM deposition by bronchial epithelial cells, suggesting that RV-induced ECM deposition is mediated through TLR. Furthermore, gene expression for fibronectin and collagen I was increased in lung homogenates of mice infected with RV-1b. RV infection and TLR ligands promote ECM deposition in isolated cell systems and RV induces ECM gene expression in vivo, thus demonstrating that RV has the potential to contribute to remodelling of the airways through induction of ECM deposition.
Modulation of monocyte-driven myositis in alphavirus infection reveals a role for CX3 CR1+ macrophages in tissue repair
Publisher: American Society for Microbiology
Date: 28-04-2020
Abstract: Arthritogenic alphaviruses cause debilitating inflammatory disease, and current therapies are restricted to palliative approaches. Here, we show that following monocyte-driven muscle inflammation, tissue recovery is associated with the accumulation of CX 3 CR1 + macrophages in the muscle. Modulating inflammatory monocyte infiltration using immune-modifying microparticles (IMP) reduced tissue damage and inflammation and enhanced the formation of tissue repair-associated CX 3 CR1 + macrophages in the muscle. This shows that modulating key effectors of viral inflammation using microparticles can alter the outcome of disease by facilitating the accumulation of macrophage subsets associated with tissue repair.
Infectious Triggers of T Cell Autoimmunity
Publisher: Elsevier
Date: 2013
Defective inflammatory monocyte development in IRF8-deficient mice abrogates migration to the West Nile virus-infected brain.
Publisher: S. Karger AG
Date: 23-09-2014
DOI: 10.1159/000365972
Abstract: IRF8 (interferon-regulatory factor-8) plays a critical role in regulating myeloid cell differentiation. However, the role of this transcription factor in the development of Ly6C+ inflammatory monocytes and their migration to the infected brain has not been examined. We have previously shown that West Nile virus (WNV) infection of wild-type (WT) mice triggers a significant increase in numbers of Ly6C+ monocytes in the bone marrow. These cells traffic via the blood to the infected brain, where they give rise to proinflammatory macrophages. Here, we show that WNV-infected IRF8-deficient (IRF8-/-) mice had significantly reduced numbers of Ly6C+ monocytes in the periphery, with few of these cells found in the blood. Furthermore, low numbers of inflammatory monocyte-derived macrophages were observed in the brains of IRF8-/- mice throughout infection. Adoptive transfer of IRF8-/- Ly6C+ monocytes demonstrated that these cells were intrinsically unable to traffic to the inflamed brain. Low expression of the chemokine receptor CCR2 and integrin VLA-4 by IRF8-/- monocytes likely contributed to this defect, as the interactions between these proteins and their ligands are critical for monocyte egress and migration to inflammatory foci. These data highlight a critical role for IRF8 in inflammatory monocyte differentiation and migration during WNV infection.
Early microglial response, myelin deterioration and lethality in mice deficient for very long chain ceramide synthesis in oligodendrocytes
Publisher: Wiley
Date: 30-12-2022
DOI: 10.1002/GLIA.24329
Abstract: The sphingolipids galactosylceramide (GalCer), sulfatide (ST) and sphingomyelin (SM) are essential for myelin stability and function. GalCer and ST are synthesized mostly from C22‐C24 ceramides, generated by Ceramide Synthase 2 (CerS2). To clarify the requirement for C22‐C24 sphingolipid synthesis in myelin biosynthesis and stability, we generated mice lacking CerS2 specifically in myelinating cells (CerS2 ΔO/ΔO ). At 6 weeks of age, normal‐appearing myelin had formed in CerS2 ΔO/ΔO mice, however there was a reduction in myelin thickness and the percentage of myelinated axons. Pronounced loss of C22‐C24 sphingolipids in myelin of CerS2 ΔO/ΔO mice was compensated by greatly increased levels of C18 sphingolipids. A distinct microglial population expressing high levels of activation and phagocytic markers such as CD64, CD11c, MHC class II, and CD68 was apparent at 6 weeks of age in CerS2 ΔO/ΔO mice, and had increased by 10 weeks. Increased staining for denatured myelin basic protein was also apparent in 6‐week‐old CerS2 ΔO/ΔO mice. By 16 weeks, CerS2 ΔO/ΔO mice showed pronounced myelin atrophy, motor deficits, and axon beading, a hallmark of axon stress. 90% of CerS2 ΔO/ΔO mice died between 16 and 26 weeks of age. This study highlights the importance of sphingolipid acyl chain length for the structural integrity of myelin, demonstrating how a modest reduction in lipid chain length causes exposure of a denatured myelin protein epitope and expansion of phagocytic microglia, followed by axon pathology, myelin degeneration, and motor deficits. Understanding the molecular trigger for microglial activation should aid the development of therapeutics for demyelinating and neurodegenerative diseases.
Microparticles bearing encephalitogenic peptides induce T-cell tolerance and ameliorate experimental autoimmune encephalomyelitis
Publisher: Springer Science and Business Media LLC
Date: 18-11-2012
DOI: 10.1038/NBT.2434
The effects of West Nile virus on major histocompatibility complex class I and II molecule expression by Lewis rat Schwann cells in vitro
Publisher: Elsevier BV
Date: 12-1991
DOI: 10.1016/0165-5728(91)90181-6
Abstract: The expression of major histocompatibility complex (MHC) class I and II molecules by Lewis rat Schwann cells after infection with West Nile virus (WNV) in vitro was examined by fluorescence microscopy and flow cytometry. WNV enhanced the expression of MHC class I molecules and induced the expression of MHC class II molecules by Schwann cells. Irradiated medium from WNV-infected Schwann cell cultures upregulated class I molecule expression on dissociated Schwann cell cultures but did not induce the expression of class II molecules. This finding has implications for virally triggered autoimmune diseases of nervous tissue.
Phase-Encoded Hyperpolarized Nanodiamond for Magnetic Resonance Imaging
Publisher: Springer Science and Business Media LLC
Date: 11-04-2019
DOI: 10.1038/S41598-019-42373-W
Abstract: Surface-functionalized nanomaterials are of interest as theranostic agents that detect disease and track biological processes using hyperpolarized magnetic resonance imaging (MRI). Candidate materials are sparse however, requiring spinful nuclei with long spin-lattice relaxation ( T 1 ) and spin-dephasing times ( T 2 ), together with a reservoir of electrons to impart hyperpolarization. Here, we demonstrate the versatility of the nanodiamond material system for hyperpolarized 13 C MRI, making use of its intrinsic paramagnetic defect centers, hours-long nuclear T 1 times, and T 2 times suitable for spatially resolving millimeter-scale structures. Combining these properties, we enable a new imaging modality, unique to nanoparticles, that exploits the phase-contrast between spins encoded with a hyperpolarization that is aligned, or anti-aligned with the external magnetic field. The use of phase-encoded hyperpolarization allows nanodiamonds to be tagged and distinguished in an MRI based on their spin-orientation alone, and could permit the action of specific bio-functionalized complexes to be directly compared and imaged.
Overcoming challenges in treating autoimmuntity: Development of tolerogenic immune-modifying nanoparticles
Publisher: Elsevier BV
Date: 06-2019
Onion-like surface design of upconverting nanophosphors modified with polyethylenimine
Publisher: SPIE
Date: 09-12-2016
DOI: 10.1117/12.2244636
Coordinated regulation and widespread cellular expression of interferon-stimulated genes (ISG) ISG-49, ISG-54, and ISG-56 in the central nervous system after infection with distinct viruses
Publisher: American Society for Microbiology
Date: 15-01-2007
DOI: 10.1128/JVI.01167-06
Abstract: The interferon (IFN)-stimulated genes (ISGs) ISG-49, ISG-54, and ISG-56 are highly responsive to viral infection, yet the regulation and function of these genes in vivo are unknown. We examined the simultaneous regulation of these ISGs in the brains of mice during infection with either lymphocytic choriomeningitis virus (LCMV) or West Nile virus (WNV). Expression of the ISG-49 and ISG-56 genes increased significantly during LCMV infection, being widespread and localized predominantly to common as well as distinct neuronal populations. Expression of the ISG-54 gene also increased but to lower levels and with a more restricted distribution. Although expression of the ISG-49, ISG-54, and ISG-56 genes was increased in the brains of LCMV-infected STAT1 and STAT2 knockout (KO) mice, this was blunted, delayed, and restricted to the choroid plexus, meninges, and endothelium. ISG-56 protein was regulated in parallel with the corresponding RNA transcript in the brain during LCMV infection in wild-type and STAT KO mice. Similar changes in ISG-49, ISG-54, and ISG-56 RNA levels and ISG-56 protein levels were observed in the brains of wild-type mice following infection with WNV. Thus, the ISG-49, ISG-54, and ISG-56 genes are coordinately upregulated in the brain during LCMV and WNV infection this upregulation, in the case of LCMV, was totally (neurons) or partially (non-neurons) dependent on the IFN-signaling molecules STAT1 and STAT2. These findings suggest a dominant role for the ISG-49, ISG-54, and ISG-56 genes in the host response to different viruses in the central nervous system, where, particularly in neurons, these genes may have nonredundant functions.
A Simulation for Flavivirus Infection Decoy Responses
Publisher: Scientific Research Publishing, Inc.
Date: 2015
An NMR investigation of the changes in plasma membrane triglyceride and phospholipid precursors during the activation of T-lymphocytes
Publisher: American Chemical Society (ACS)
Date: 22-09-1992
DOI: 10.1021/BI00152A054
Abstract: Two-dimensional 1H-NMR spectroscopy was used to quantify the level of isotropically tumbling plasma membrane triglyceride and the intracellular concentrations of water-soluble phospholipid precursors during the activation of thymic T-lymphocytes. The concentration of "mobile" triglyceride in the plasma membrane was seen to increase 25-fold during 72 h of activation of murine thymic T-lymphocytes with ionomycin and phorbol myristate acetate. This is the first unequivocal demonstration of such a dramatic increase in mobile plasma membrane triglyceride during T-lymphocyte activation and leads to the suggestion that immune cell activation is associated with increased plasma membrane fluidity. The intracellular concentrations of choline- and ethanolamine-based phospholipid precursors were shown to increase during the early stages of T-lymphocyte activation and then remain at levels above those in resting cells. This may facilitate de novo phospholipid biosynthesis, which is presumably necessary since cell volume, and hence the plasma membrane surface area, was demonstrated to increase significantly during thymocyte activation.
Immunosuppressive effects of Tripterygium wilfordii hook F in a rat liver transplant model
Publisher: Elsevier BV
Date: 02-2001
Autologous lymphocyte-monocyte co-culture increases NMR-visible and cytoplasmic lipids in the absence of increased markers of lymphocyte activation
Publisher: Elsevier BV
Date: 10-2001
DOI: 10.1016/S1388-1981(01)00157-3
Abstract: Alterations in nuclear magnetic resonance (NMR)-visible lipid, morphometric lipid volume fraction, distribution of subcellular lipid droplets and activation antigen expression were examined in human peripheral blood lymphocytes, activated using phorbol myristate acetate (PMA) and ionomycin or by co-culture with autologous monocytes. PMA/Ionomycin treatment caused significant time-dependent increases in mobile lipid and in oil red O-positive lipid droplets that were accompanied by lymphocyte proliferation and increases in activation antigens, CD25, CD69 and CD71. Co-culture of lymphocytes and monocytes also induced significant increases in NMR-visible lipid signals and cytoplasmic lipid droplets, but in contrast, no correspondent increases in activation antigens were observed. Strong correlations were observed between the intensity of the NMR signal and the percentage of total cells containing lipid droplets (r=0.95) and the morphometric lymphocyte lipid volume fraction (r=0.80), indicating that the droplets were the source of the mobile lipid signal. Lipid droplets in PMA/Ionomycin-treated cells were evenly distributed throughout the population, but in co-cultures, only lymphocytes in close proximity to monocytes with lipid droplets contained oil red O-positive lipid. This data shows that the NMR-visible mobile lipid signal observed in lymphocytes co-cultured with monocytes is not directly dependent on either proliferation or the upregulation of activation antigens, similar to the previously observed response of T cells exposed to antibodies to the T cell receptor.
Immovable Object Meets Unstoppable Force? Dialogue Between Resident and Peripheral Myeloid Cells in the Inflamed Brain
Publisher: Frontiers Media SA
Date: 08-12-2020
DOI: 10.3389/FIMMU.2020.600822
Abstract: Inflammation of the brain parenchyma is characteristic of neurodegenerative, autoimmune, and neuroinflammatory diseases. During this process, microglia, which populate the embryonic brain and become a permanent sentinel myeloid population, are inexorably joined by peripherally derived monocytes, recruited by the central nervous system. These cells can quickly adopt a morphology and immunophenotype similar to microglia. Both microglia and monocytes have been implicated in inducing, enhancing, and/or maintaining immune-mediated pathology and thus disease progression in a number of neuropathologies. For many years, experimental and analytical systems have failed to differentiate resident microglia from peripherally derived myeloid cells accurately. This has impeded our understanding of their precise functions in, and contributions to, these diseases, and h ered the development of novel treatments that could target specific cell subsets. Over the past decade, microglia have been investigated more intensively in the context of neuroimmunological research, fostering the development of more precise experimental systems. In light of our rapidly growing understanding of these cells, we discuss the differential origins of microglia and peripherally derived myeloid cells in the inflamed brain, with an analysis of the problems resolving these cell types phenotypically and morphologically, and highlight recent developments enabling more precise identification.
Induction of class I major histocompatibility complex antigen expression by West Nile virus on γ interferon-refractory early murine trophoblast cells
Publisher: Proceedings of the National Academy of Sciences
Date: 02-1989
Abstract: Primary murine trophoblast giant cells (TGC) do not express detectable major histocompatibility complex (MHC) antigens and are refractory to the MHC-increasing effects of alpha and beta (virus-induced) interferons and gamma (immune type) interferon during early implantation (postcoital days 3.5-6). West Nile virus infection of primary TGC monolayers from postcoital-day-3.5 preimplantation blastocysts induced paternal MHC antigen expression within 16 hr, as detected by immunogold labeling for electron microscopy. Induction is unlikely to have been mediated by secreted virus-induced interferons or other factors, as it occurred in the presence of high concentrations of anti-alpha/beta interferon antibodies and was not induced by virus-inactivated supernatants from MHC-induced primary TGC cultures. Attempts to induce MHC antigen expression with poly(I.C) or recombinant tumor necrosis factor alpha in primary TGC cultures also failed. Thus, the apparent inhibition of MHC antigen expression in primary TGC during early implantation and their refractoriness to induction of de novo MHC antigen expression is not absolute. This may represent a maternal-and/or species-protective evolutionary device. As such, manipulation of this phenomenon may allow a conclusive assessment of the significance of inhibition of MHC antigen expression on trophoblast cells in the implanting semiallogeneic embryo.
Unexpected effects of pathogens on epithelial Na+ channels
Publisher: Korean Academy of Medical Sciences
Date: 2000
Contribution of STAT1 to innate and adaptive immunity during type I interferon-mediated lethal virus infection
Publisher: Public Library of Science (PLoS)
Date: 20-04-2020
Novel role of GPR109A in thymic regulatory T cell development
Publisher: Research Square Platform LLC
Date: 23-02-2023
DOI: 10.21203/RS.3.RS-2609653/V1
Abstract: Regulatory T cells (Treg) maintain immune homeostasis due to their anti-inflammatory functions. They can be generated either centrally in the thymus or in peripheral organs. Metabolites such as short chain fatty acids produced by intestinal microbiota can induce peripheral Treg differentiation, by activating G-protein-coupled-receptors like GPR109A. In this study, we identified a novel role for GPR109A on thymic Treg development. We found that Gpr109a-/- mice had increased Treg under basal conditions in multiple organs compared to wild type mice (WT). GPR109A was not expressed on T cells but on medullary thymic epithelial cells (mTECs), as revealed by single cell RNA sequencing in both mice and humans and confirmed by flow cytometry in mice. mTECs isolated from Gpr109a-/- mice had higher expression of autoimmune regulator (AIRE), the key regulator of Treg development, while the subset of mTECs that did not express Gpr109a displayed increased Aire expression and enhanced signalling related to mTEC functionality as well. Increased thymic Treg in Gpr109a-/- mice was associated with protection from experimental autoimmune encephalomyelitis, with ameliorated clinical signs and reduced inflammation. This work identifies a novel role for GPR109A and by extension, the gut microbiota, on thymic Treg development via its regulation of mTECs.
High-parameter Cytometry Unmasks Microglial Cell Spatio-temporal Response Kinetics in Severe Neuroinflammatory Disease.
Publisher: Research Square Platform LLC
Date: 07-04-2021
DOI: 10.21203/RS.3.RS-388801/V1
Abstract: Background: Differentiating infiltrating myeloid cells from resident microglia in neuroinflammatory disease is challenging, because bone marrow-derived inflammatory monocytes infiltrating the inflamed brain adopt a ‘microglia-like’ phenotype. This precludes the accurate identification of either cell type without genetic manipulation, which is important to understand their temporal contribution to disease and inform effective intervention in its pathogenesis. During West Nile virus (WNV) encephalitis, widespread neuronal infection drives substantial CNS infiltration of inflammatory monocytes, causing severe immunopathology and/or death, but the role of microglia in this remains unclear. Methods: Using high-parameter cytometry and dimensionality-reduction, we devised a simple, novel gating strategy to identify microglia and infiltrating myeloid cells under extreme inflammatory conditions. Validating our strategy we 1) blocked the entry of infiltrating myeloid populations from peripheral blood using monoclonal blocking antibodies, 2) adoptively transferred BM-derived monocytes and tracked their phenotypic changes after infiltration and 3) labelled peripheral leukocytes that infiltrate into the brain with an intravenous dye. We demonstrated that myeloid immigrants populated only the identified macrophage gates, while PLX5622 depletion reduced all 4 subsets defined by the microglial gates. Results: Using this novel gating approach, we identified four consistent microglia subsets in the homeostatic and WNV-infected brain. These were P2RY12 hi CD86 - , P2RY12 hi CD86 + , and P2RY12 lo CD86 - P2RY12 lo CD86 + . During infection, 2 further populations were identified as inflammatory and microglia-like macrophages, recruited from the bone marrow. Detailed kinetic analysis showed significant increases in the proportions of both P2RY12 lo microglia subsets in all anatomical areas, largely at the expense of the P2RY12 hi CD86 - subset, with the latter undergoing compensatory proliferation, suggesting replenishment of, and differentiation from this subset in response to infection. Microglia altered their morphology early in infection, with all cells adopting temporal and regional disease-specific phenotypes. Late in disease, microglia produced IL-12, downregulated CX3CR1, F4/80 and TMEM119 and underwent apoptosis. Infiltrating macrophages expressed both TMEM119 and P2RY12 de novo, with the microglia-like subset notably exhibiting the highest proportional myeloid population death. Conclusions: Our approach enables detailed kinetic analysis of resident vs infiltrating myeloid cells in a wide range of neuroinflammatory models without non-physiological manipulation. This will more clearly inform potential therapeutic approaches that specifically modulate these cells.
Na(+)-dependent high affinity uptake of L-glutamate in primary cultures of human fibroblasts isolated from three different types of tissue.
Publisher: Wiley
Date: 14-02-1994
DOI: 10.1016/0014-5793(94)80382-X
Abstract: Cultured human fibroblasts isolated from embryonic muscle, skin and peripheral nerve tissues were found to accumulate [3H]L-glutamate by a Na(+)-dependent uptake process strongly inhibited by several glutamate/aspartate analogues including D- and L-aspartate, D- and L-threo-3-hydroxyaspartate and L-trans-pyrrolidine-2,4-dicarboxylate but not D-glutamate. It was also reduced by elevated concentrations of K+, Rb+ and Cs+. The values of Km's were 5-20 microM, well within the 'high affinity' region. Variations in the capacity (Vmax) of [3H]L-glutamate uptake did not correlate with the origin (muscle, skin or nerve tissue) of the fibroblasts. The uptake characteristics suggest that it is mediated by a transport system similar to that commonly observed only in brain tissue.
Integration, exploration, and analysis of high‐dimensional single‐cell cytometry data using Spectre
Publisher: Wiley
Date: 26-04-2022
DOI: 10.1002/CYTO.A.24350
Abstract: As the size and complexity of high‐dimensional (HD) cytometry data continue to expand, comprehensive, scalable, and methodical computational analysis approaches are essential. Yet, contemporary clustering and dimensionality reduction tools alone are insufficient to analyze or reproduce analyses across large numbers of s les, batches, or experiments. Moreover, approaches that allow for the integration of data across batches or experiments are not well incorporated into computational toolkits to allow for streamlined workflows. Here we present Spectre, an R package that enables comprehensive end‐to‐end integration and analysis of HD cytometry data from different batches or experiments. Spectre streamlines the analytical stages of raw data pre‐processing, batch alignment, data integration, clustering, dimensionality reduction, visualization, and population labelling, as well as quantitative and statistical analysis. Critically, the fundamental data structures used within Spectre, along with the implementation of machine learning classifiers, allow for the scalable analysis of very large HD datasets, generated by flow cytometry, mass cytometry, or spectral cytometry. Using open and flexible data structures, Spectre can also be used to analyze data generated by single‐cell RNA sequencing or HD imaging technologies, such as Imaging Mass Cytometry. The simple, clear, and modular design of analysis workflows allow these tools to be used by bioinformaticians and laboratory scientists alike. Spectre is available as an R package or Docker container. R code is available on Github ( mmunedynamics/spectre ).
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