ORCID Profile
0000-0002-9027-2098
Current Organisations
Monash University
,
Murdoch University
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Publisher: Wiley
Date: 04-2009
Abstract: mAb that recognise various cell surface receptors have been used to deliver antigen to DC and thereby elicit immune responses. The encouraging data obtained in mouse models suggests that this immunisation strategy is efficient and could lead to clinical trials. We discuss a number of issues pertinent to this vaccination approach. These include which molecules are the best targets for delivering antigen to DC, which DC subtypes should be targeted, the types of immune responses to be generated and whether additional adjuvants are required. Finally, we discuss some progress towards targeting antigen to human DC.
Publisher: Oxford University Press (OUP)
Date: 04-2001
Abstract: Dendritic cells (DC), in their role in initiation of the adaptive immune response, have been extensively studied for their capacity to interact and stimulate naive T cells. Subsets of mature murine DC isolated directly from the spleen have been shown to differ in their ability to induce proliferative responses in both primary CD4(+) and primary CD8(+) T cells the myeloid-related CD8alpha(-) DC induce a more intense or prolonged proliferation of naive T cells than do the lymphoid-related DC bearing CD8alpha despite similar expression of MHC and co-stimulatory molecules. Here we examine the interaction of these DC subpopulations with T cells already in the activated or memory state which are known to have greater sensitivity to antigen stimulation and bear receptors with increased capacity for signal transduction. We show that influenza virus-specific CD4(+) T cell clones and splenic T cells from peptide-primed animals proliferated in response to antigen presented by separated splenic CD8(-) DC. In contrast, these T cells showed only weak, if any, proliferation in response to CD8(+) DC despite observable cluster formation in the cultures. The differential between the two DC types in inducing proliferation was even more pronounced than previously seen with primary T cells and did not reflect differential longevity of the DC in culture, altered response kinetics or deviation from IL-2 to IL-4 induction with CD8(+) DC, but was related to the levels of IL-2 induced. The deficiency in the CD8(+) DC was not overcome by using infectious virus rather than synthetic peptide as the antigen source. These results show that lymphoid-related CD8(+) splenic DC, despite their mature phenotype, fail to provide appropriate signals to secondary CD4(+) T cells to sustain their proliferation.
Publisher: Elsevier BV
Date: 02-2006
Publisher: The American Association of Immunologists
Date: 15-11-2013
Abstract: The response of B cells to Ag targeted to Clec9A on dendritic cells was followed using the hapten nitrophenol (NP) conjugated to rat Ig carrier. Injection of small amounts of NP conjugated to anti-Clec9A in the absence of adjuvants gave high and very prolonged Ab responses, approaching those obtained by high doses of nontargeted NP–protein conjugates with alum adjuvant. The response to NP–anti-Clec9A included the transient formation of germinal centers, maturation of Ab affinity, and some memory B cell formation. Serum Ab titers remained high 35 wk postimmunization, well after the initial follicular response had faded. The results suggest Clec9A-targeting strategies for improving Ab responses to vaccine Ags.
Publisher: Springer Science and Business Media LLC
Date: 2013
DOI: 10.1186/AR4250
Publisher: The American Association of Immunologists
Date: 15-07-2011
Abstract: Three surface molecules of mouse CD8+ dendritic cells (DCs), also found on the equivalent human DC subpopulation, were compared as targets for Ab-mediated delivery of Ags, a developing strategy for vaccination. For the production of cytotoxic T cells, DEC-205 and Clec9A, but not Clec12A, were effective targets, although only in the presence of adjuvants. For Ab production, however, Clec9A excelled as a target, even in the absence of adjuvant. Potent humoral immunity was a result of the highly specific expression of Clec9A on DCs, which allowed longer residence of targeting Abs in the bloodstream, prolonged DC Ag presentation, and extended CD4 T cell proliferation, all of which drove highly efficient development of follicular helper T cells. Because Clec9A shows a similar expression pattern on human DCs, it has particular promise as a target for vaccines of human application.
Publisher: Public Library of Science (PLoS)
Date: 13-04-2016
Publisher: Elsevier BV
Date: 09-2001
DOI: 10.1016/S0161-5890(01)00067-0
Abstract: Dendritic cells (DC) are potent antigen presenting cells that activate naive T cells. It is becoming increasingly clear that DC are not a homogeneous cell population, but comprise different subpopulations that differ in ontogeny and function. To further the molecular characterisation of DC, we screened for genes that were differentially expressed amongst DC subsets and could therefore give insight into their varying biological functions. Using Representational Difference Analysis (RDA) we identified a gene (CIRE) that is expressed at higher levels in the myeloid-related CD8alpha(-) DC than in the lymphoid-related CD8alpha(+) DC. CIRE is a 238 amino acid type II membrane protein, of approximately 33 kDa in size, whose extracellular region contains a C-type lectin domain. Northern blot analysis revealed that CIRE is almost exclusively expressed in DC and was not detected in organs such as heart, brain, kidney, liver, and thymus. T cells failed to express message for CIRE, whilst B cells expressed very low levels. These data here further substantiated by Northern blot analysis of 18 cell lines of various origins (myeloid, macrophage, B and T cell) where only one cell line, which was of myeloid origin and could give rise to DC, expressed mRNA for CIRE. Semi-quantitative RT-PCR suggested that CIRE is down-regulated upon activation. CIRE shares 57% identity with human DC-SIGN, a molecule that has been shown to be the ligand of ICAM-3 and that is also a receptor that binds HIV and facilitates trans-infection of T cells.
Publisher: Wiley
Date: 19-12-2022
Abstract: Antibodies are hallmarks of most effective vaccines. For successful T‐dependent antibody responses, conventional dendritic cells (cDC) have been largely attributed the role of priming T cells. By contrast, follicular dendritic cells and macrophages have been seen as responsible for B cell activation, due to their strategic location within secondary lymphoid tissues and capacity to present native antigen to B cells. This review summarizes the mounting evidence that cDC can also present native antigen to B cells. cDC2 have been the main subset linked to humoral responses, based largely on their favorable location, capacity to prime CD4 + T cells, and ability to present native antigen to B cells. However, studies using strategies to deliver antigen to receptors on cDC1, reveal this subset can also contribute to naïve B cell activation, as well as T cell priming. cDC1 location within lymphoid tissues reveals their juxtaposition to B cell follicles, with ready access to B cells for presentation of native antigen. These findings support the view that both cDC1 and cDC2 are capable of initiating humoral responses provided antigen is captured by relevant surface receptors attuned to this process. Such understanding is fundamental for the development of innovative humoral vaccination approaches.
Publisher: American Society for Clinical Investigation
Date: 19-05-2016
Publisher: Rockefeller University Press
Date: 08-10-2007
DOI: 10.1084/JEM.20071351
Abstract: Interferon-producing killer dendritic cells (IKDCs) have been described as possessing the lytic potential of NK cells and the antigen-presenting capacity of dendritic cells (DCs). In this study, we examine the lytic function and antigen-presenting capacity of mouse spleen IKDCs, including those found in DC preparations. IKDCs efficiently killed NK cell targets, without requiring additional activation stimuli. However, in our hands, when exposed to protein antigen or to MHC class II peptide, IKDCs induced little or no T cell proliferation relative to conventional DCs or plasmacytoid DCs, either before or after activation with CpG, or in several disease models. Certain developmental features indicated that IKDCs resembled NK cells more than DCs. IKDCs, like NK cells, did not express the transcription factor PU.1 and were absent from recombinase activating gene-2–null, common γ-chain–null (Rag2−/−Il2rg−/−) mice. When cultured with IL-15 and -18, IKDCs proliferated extensively, like NK cells. Under these conditions, a proportion of expanded IKDCs and NK cells expressed high levels of surface MHC class II. However, even such MHC class II+ IKDCs and NK cells induced poor T cell proliferative responses compared with DCs. Thus, IKDCs resemble NK cells functionally, and neither cell type could be induced to be effective antigen-presenting cells.
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.IMMUNI.2016.08.011
Abstract: In recent years, various intervention strategies have reduced malaria morbidity and mortality, but further improvements probably depend upon development of a broadly protective vaccine. To better understand immune requirement for protection, we examined liver-stage immunity after vaccination with irradiated sporozoites, an effective though logistically difficult vaccine. We identified a population of memory CD8
Publisher: Springer Science and Business Media LLC
Date: 06-04-2009
DOI: 10.1038/NI.1724
Abstract: Skin-derived dendritic cells (DCs) include Langerhans cells, classical dermal DCs and a langerin-positive CD103(+) dermal subset. We examined their involvement in the presentation of skin-associated viral and self antigens. Only the CD103(+) subset efficiently presented antigens of herpes simplex virus type 1 to naive CD8(+) T cells, although all subsets presented these antigens to CD4(+) T cells. This showed that CD103(+) DCs were the migratory subset most efficient at processing viral antigens into the major histocompatibility complex class I pathway, potentially through cross-presentation. This was supported by data showing only CD103(+) DCs efficiently cross-presented skin-derived self antigens. This indicates CD103(+) DCs are the main migratory subtype able to cross-present viral and self antigens, which identifies another level of specialization for skin DCs.
Publisher: The American Association of Immunologists
Date: 15-02-2014
Abstract: We established a humanized mouse model incorporating FLT3-ligand (FLT3-L) administration after hematopoietic cell reconstitution to investigate expansion, phenotype, and function of human dendritic cells (DC). FLT3-L increased numbers of human CD141+ DC, CD1c+ DC, and, to a lesser extent, plasmacytoid DC (pDC) in the blood, spleen, and bone marrow of humanized mice. CD1c+ DC and CD141+ DC subsets were expanded to a similar degree in blood and spleen, with a bias toward expansion of the CD1c+ DC subset in the bone marrow. Importantly, the human DC subsets generated after FLT3-L treatment of humanized mice are phenotypically and functionally similar to their human blood counterparts. CD141+ DC in humanized mice express C-type lectin-like receptor 9A, XCR1, CADM1, and TLR3 but lack TLR4 and TLR9. They are major producers of IFN-λ in response to polyinosinic-polycytidylic acid but are similar to CD1c+ DC in their capacity to produce IL-12p70. Although all DC subsets in humanized mice are efficient at presenting peptide to CD8+ T cells, CD141+ DC are superior in their capacity to cross-present protein Ag to CD8+ T cells following activation with polyinosinic-polycytidylic acid. CD141+ DC can be targeted in vivo following injection of Abs against human DEC-205 or C-type lectin-like receptor 9A. This model provides a feasible and practical approach to dissect the function of human CD141+ and CD1c+ DC and evaluate adjuvants and DC-targeting strategies in vivo.
Publisher: American Society for Clinical Investigation
Date: 09-04-2018
DOI: 10.1172/JCI96791
Publisher: Oxford University Press (OUP)
Date: 28-03-2006
Publisher: The American Association of Immunologists
Date: 02-2019
Abstract: CD4+ T cell responses are crucial for the control of many intracellular pathogens, yet the requirements for their induction are not fully understood. To better understand the role that various dendritic cell (DC) subtypes play in CD4+ T cell priming, we compared in vivo T cell responses to skin inoculation of mice with infectious or UV-inactivated HSV type 1. Localized infection elicited a Th1 response that was primed in skin-draining lymph nodes involving Ag presentation by migratory dermal and lymph node–resident DC. However, expansion and Th1 differentiation was impaired in response to UV-inactivated virus (UV-HSV), and this defect correlated with a restriction of Ag presentation to migratory CD103– dermal DC. A similar differentiation defect was seen in infected mice lacking CD8α+ and CD103+ classical type 1 DC (cDC1). Finally, Th1 differentiation after UV-HSV inoculation was rescued by targeted Ag delivery to CD8α+ and CD103+ cDC1 using an anti-Clec9A Ab construct. This suggests that Ag presentation by cDC1 is crucial for optimal Th1 immunity to HSV type 1 infection and potentially other pathogens of the skin.
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.CELREP.2018.08.094
Abstract: Liver tissue-resident memory T (Trm) cells migrate throughout the sinusoids and are capable of protecting against malaria sporozoite challenge. To gain an understanding of liver Trm cell development, we examined various conditions for their formation. Although liver Trm cells were found in naive mice, their presence was dictated by antigen specificity and required IL-15. Liver Trm cells also formed after adoptive transfer of in vitro-activated but not naive CD8
Publisher: Wiley
Date: 11-05-2009
Publisher: Springer Science and Business Media LLC
Date: 2009
Publisher: Springer Science and Business Media LLC
Date: 06-11-2017
DOI: 10.1038/S41541-017-0033-5
Abstract: Targeting model antigens (Ags) to Clec9A on DC has been shown to induce, not only cytotoxic T cells, but also high levels of Ab. In fact, Ab responses against immunogenic Ag were effectively generated even in the absence of DC-activating adjuvants. Here we tested if targeting weakly immunogenic putative subunit vaccine Ags to Clec9A could enhance Ab responses to a level likely to be protective. The proposed “universal” influenza Ag, M2e and the enterovirus 71 Ag, SP70 were linked to anti-Clec9A Abs and injected into mice. Targeting these Ags to Clec9A greatly increased Ab titres. For optimal responses, a DC-activating adjuvant was required. For optimal responses, a boost injection was also needed, but the high Ab titres against the targeting construct blocked Clec9A-targeted boosting. Heterologous prime-boost strategies avoiding cross-reactivity between the priming and boosting targeting constructs overcame this limitation. In addition, targeting small amounts of Ag to Clec9A served as an efficient priming for a conventional boost with higher levels of untargeted Ag. Using this Clec9A-targeted priming, conventional boosting strategy, M2e immunisation protected mice from infection with lethal doses of influenza H1N1 virus.
Publisher: Elsevier BV
Date: 02-2012
Abstract: Delivering antigens directly to dendritic cells (DCs) in situ, by injecting antigens coupled to antibodies specific for DC surface molecules, is a promising strategy for enhancing vaccine efficacy. Enhanced cytotoxic T cell responses are obtained if an adjuvant is co-administered to activate the DC. Such DC targeting is also effective at enhancing humoral immunity, via the generation of T follicular helper cells. Depending on the DC surface molecule targeted, antibody production can be enhanced even in the absence of adjuvants. In the case of Clec9A as the DC surface target, enhanced antibody production is a consequence of the DC-restricted expression of the target molecule. Few other cells absorb the antigen-antibody construct, therefore, it persists in the bloodstream, allowing sustained antigen presentation, even by non-activated DCs.
Publisher: American Society of Hematology
Date: 15-10-2008
DOI: 10.1182/BLOOD-2008-05-155176
Abstract: A novel dendritic cell (DC)–restricted molecule, Clec9A, was identified by gene expression profiling of mouse DC subtypes. Based on sequence similarity, a human ortholog was identified. Clec9A encodes a type II membrane protein with a single extracellular C-type lectin domain. Both the mouse Clec9A and human CLEC9A were cloned and expressed, and monoclonal antibodies (mAbs) against each were generated. Surface staining revealed that Clec9A was selective for mouse DCs and was restricted to the CD8+ conventional DC and plasmacytoid DC subtypes. A subset of human blood DCs also expressed CLEC9A. A single injection of mice with a mAb against Clec9A, which targets antigens (Ags) to the DCs, produced a striking enhancement of antibody responses in the absence of added adjuvants or danger signals, even in mice lacking Toll-like receptor signaling pathways. Such targeting also enhanced CD4 and CD8 T-cell responses. Thus, Clec9A serves as a new marker to distinguish subtypes of both mouse and human DCs. Furthermore, targeting Ags to DCs with antibodies to Clec9A is a promising strategy to enhance the efficiency of vaccines, even in the absence of adjuvants.
Publisher: Frontiers Media SA
Date: 2013
Publisher: Elsevier BV
Date: 07-2017
DOI: 10.1016/J.IMMUNI.2017.06.021
Abstract: Lung infections cause prolonged immune alterations and elevated susceptibility to secondary pneumonia. We found that, after resolution of primary viral or bacterial pneumonia, dendritic cells (DC), and macrophages exhibited poor antigen-presentation capacity and secretion of immunogenic cytokines. Development of these "paralyzed" DCs and macrophages depended on the immunosuppressive microenvironment established upon resolution of primary infection, which involved regulatory T (Treg) cells and the cytokine TGF-β. Paralyzed DCs secreted TGF-β and induced local Treg cell accumulation. They also expressed lower amounts of IRF4, a transcription factor associated with increased antigen-presentation capacity, and higher amounts of Blimp1, a transcription factor associated with tolerogenic functions, than DCs present during primary infection. Blimp1 expression in DC of humans suffering sepsis or trauma correlated with severity and complicated outcomes. Our findings describe mechanisms underlying sepsis- and trauma-induced immunosuppression, reveal prognostic markers of susceptibility to secondary infections and identify potential targets for therapeutic intervention.
Publisher: Elsevier BV
Date: 02-2013
DOI: 10.1038/KI.2012.374
Abstract: The CD40-CD154 costimulatory pathway has been shown to be critical for both T- and B-cell activation in autoimmune disease. Here, we assessed the effects of blocking this pathway using CD40 DNA vaccine enhanced by dendritic cell targeting on the development of active Heymann nephritis, a rat model of human membranous nephropathy. DNA vaccination delivers plasmid DNA encoding the target antigen, either alone or in combination with enhancing elements, to induce both humoral and cellular immune responses. To determine whether CD40 DNA vaccine targeting the encoded CD40 directly to dendritic cells would improve the efficacy of the vaccination against self-protein CD40, we utilized a plasmid encoding a single-chain Fv antibody specific for the dendritic cell-restricted antigen-uptake receptor DEC205 (scDEC), the target gene CD40, and the adjuvant tetanus sequence p30. This vaccine plasmid was compared to a control plasmid without scDEC. Rats vaccinated with scDEC-CD40 had significantly less proteinuria and renal injury than did rats receiving scControl-CD40 and were protected from developing Heymann nephritis. Thus, CD40 DNA vaccination targeted to dendritic cells limits the development of Heymann nephritis.
Publisher: Rockefeller University Press
Date: 22-08-2011
DOI: 10.1084/JEM.20110538
Abstract: Cells undergoing programmed cell death (apoptosis) are removed in situ by macrophages and dendritic cells (DCs) through a specialized form of phagocytosis (efferocytosis). In the lung, there are two primary DC subsets with the potential to migrate to the local lymph nodes (LNs) and initiate adaptive immune responses. In this study, we show that only CD103+ DCs were able to acquire and transport apoptotic cells to the draining LNs and cross present apoptotic cell–associated antigen to CD8 T cells. In contrast, both the CD11bhi and the CD103+ DCs were able to ingest and traffic latex beads or soluble antigen. CD103+ DCs selectively exhibited high expression of TLR3, and ligation of this receptor led to enhanced in vivo cytotoxic T cell responses to apoptotic cell–associated antigen. The selective role for CD103+ DCs was confirmed in Batf3−/− mice, which lack this DC subtype. Our findings suggest that CD103+ DCs are the DC subset in the lung that captures and presents apoptotic cell–associated antigen under homeostatic and inflammatory conditions and raise the possibility for more focused immunological targeting to CD8 T cell responses.
Publisher: Wiley
Date: 10-2005
Abstract: Targeting antigen to dendritic cells (DC) in vivo might be an effective method of modulating immune responses. Given the functional specializations among DC subsets, we investigated how targeting different receptors on different DC subsets may influence antibody (Ab) production. We show here that targeting FIRE (F4/80-like receptor) or CIRE (C-type lectin receptor), two molecules expressed on the surface of immature CD8- DC in the mouse, increases Ab production 100-1000-fold over a non-targeted control. This response was equivalent to that achieved with CpG adjuvant. In contrast, targeting CD205, which is primarily expressed on CD8+ DC, did not elicit an Ab response unless an adjuvant was added. Strong Ab responses in FcRgamma-/- mice, and with the use of F(ab')2 fragments, confirmed that FIRE and CIRE targeting was due to specific rather than FcR or complement binding. Our findings may reflect differences in the ability of CD8+ and CD8- DC subsets to stimulate immune responses in vivo. Although the consensus view is that Ag presentation on DC in their steady state leads to tolerance, the Ab enhancement from FIRE and CIRE targeting in the apparent absence of any "danger" or inflammatory signal would suggest that targeting certain DC molecules can supplant the need for external adjuvants for eliciting immune responses.
Publisher: Springer New York
Date: 22-11-2012
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.MOLIMM.2016.12.010
Abstract: Targeting antigen (Ag) to dendritic cell (DC) surface receptors is a potential new mode of vaccination. C-type lectin-like receptors Clec9A and Clec12A are attractive receptor targets however their targeting in vivo elicits significantly different outcomes for unknown reasons. To gain insight into the mechanisms responsible, we have examined the intrinsic capacity of Clec9A and Clec12A to elicit MHC I and MHC II Ag presentation following ex vivo targeting with primary murine DC. Both receptors exhibited high rates of internalization by CD8
Publisher: American Society of Hematology
Date: 12-10-2007
DOI: 10.1182/BLOOD-2006-05-015354
Abstract: The capacity of mouse spleen conventional dendritic cells (cDCs) and plasmacytoid dendritic cells (pDCs) to produce interferon-γ (IFN-γ) or IFN-α was assessed, and compared with that of natural killer (NK) cells and the recently identified interferon-producing killer dendritic cells (IKDCs), both of which are frequent contaminants in DC preparations. Fully developed cDCs or pDCs, if free of NK cells or IKDCs, showed little capacity for IFN-γ production. However, an early developmental form of the CD4−8+ cDC subtype, and the Ly6C− Ly49Q− pDC subtype, both were able to produce moderate amounts of IFN-γ, although less than IKDCs. In response to toll-like receptor 9 stimuli, both the Ly6C+ Ly49Q+ and the Ly6C− Ly49Q− pDC subtypes were effective producers of IFN-α. However, IKDCs, which efficiently produced IFN-γ and showed immediate cytotoxicity on NK target cells, did not produce IFN-α un-der these conditions.
Publisher: Wiley
Date: 18-04-2013
Abstract: A new class of targeted and immune-evading nanocarrier made using only biological components and facile processes is assembled in a bottom-up fashion. Simple top-down sequential addition of immune-evading or receptor-specific antibody elements conjugated to biosurfactant protein DAMP4 promotes self-assembly at an interface previously formed in the presence of peptide surfactant AM1, leading to a functional display at the interface through non-covalent molecular self-assembly.
Publisher: The American Association of Immunologists
Date: 08-2015
Abstract: Targeting Ags to dendritic cell (DC) surface receptors can induce a variety of responses depending on the DC type targeted, the receptor targeted, and the adjuvant used. Clec9A (DNGR-1), which is expressed by CD8+ DCs, has been shown to bind F-actin exposed on damaged cells. Targeting Ag to this receptor in mice and nonhuman primates induces strong humoral immunity even in the absence of adjuvant, a process seen for a few select DC receptors. In contrast with other receptors, however, targeting Clec9A induces long-lived, affinity-matured Ab responses that are associated with efficient CD4+ T cell responses shown to possess properties of follicular Th cells (TFH). In this article, we provide definitive evidence that Clec9A targeting promotes the development of TFH by showing that responding CD4 T cells express CXCR5, PD1, the TFH transcription factor Bcl6, and the cytokine IL-21, and that these cells localize to germinal centers. Furthermore, we extend studies from the model Ag OVA to the viral Ag glycoprotein D of HSV-1 and examine the capacity of primed TFH to form functional memory. We show that targeting glycoprotein D to Clec9A even in the absence of adjuvant induced long-lived memory CXCR5+ PD1hi CD4+ T cells that proliferated extensively upon secondary challenge and rapidly developed into effector TFH. This was associated with enhanced germinal center B cell responses and accelerated Ab production. Our study indicates that targeting Ags to Clec9A in the absence of adjuvant routinely generates TFH responses that form long-lived memory capable of robust secondary TFH responses.
Publisher: Informa UK Limited
Date: 2006
DOI: 10.1080/10425170500355737
Abstract: The epidermal growth factor-transmembrane seven (EGF-TM7) family are proteins that express EGF-like domains at their extracellular N-terminus coupled to a classical seven transmembrane (TM7) cassette. Recently, we identified, in mice, a novel member of this family termed FIRE (EMR-4). Here, we present the structure of the mouse and human FIRE genes. The structures of the two genes are strikingly similar, with the positions of the introns, relative to the deduced protein sequences, highly conserved. Moreover, the gene structures are typical of other members of the EGF-TM7 family. Other researchers have identified a point deletion in exon eight of the human FIRE gene, which introduces a frame shift into the cDNA leading to a premature stop codon. Thus, human FIRE is predicted to be expressed only as a soluble protein even though sequence potentially encoding the TM7 cassette is found in a separate open reading frame of the same mRNA transcript. We explored the possibility that a cell surface expressed form of human FIRE did exist, either as an allelic variant, or as an alternatively spliced transcript. Although, we did identify two alternatively spliced human FIRE transcripts, neither are predicted to express the TM7 cassette. Thus if human FIRE exists, it is likely to be expressed as a soluble secreted molecule.
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.MOLIMM.2016.11.015
Abstract: We have previously shown that DEC205, a surface receptor expressed at high levels on CD8
Publisher: Wiley
Date: 06-02-2013
Abstract: Bone marrow stromal cell-2 (BST-2) has major roles in viral tethering and modulation of interferon production. Here we investigate BST-2 as a receptor for the delivery of antigen to dendritic cells (DCs). We show that BST-2 is expressed by a panel of mouse and human DC subsets, particularly under inflammatory conditions. The outcome of delivering antigen to BST-2 expressed by steady state and activated plasmacytoid DC (pDC) or conventional CD8(+) and CD8(-) DCs was determined. T-cell responses were measured for both MHC class I (MHCI) and MHC class II (MHCII) antigen presentation pathways in vitro. Delivering antigen via BST-2 was compared with that via receptors DEC205 or Siglec-H. We show that despite a higher antigen load and faster receptor internalisation, when antigen is delivered to steady state or activated pDC via BST-2, BST-2-targeted activated conventional DCs present antigen more efficiently. Relative to DEC205, BST-2 was inferior in its capacity to deliver antigen to the MHCI cross-presentation pathway. In contrast, BST-2 was superior to Siglec-H at initiating either MHCI or MHCII antigen presentation. In summary, BST-2 is a useful receptor to target with antigen, given its broad expression pattern and ability to access both MHCI and MHCII presentation pathways with relative efficiency.
Publisher: Elsevier BV
Date: 09-2015
DOI: 10.1038/MI.2014.133
Abstract: Influenza virus gains entry into the body by inhalation and initiates its replication cycle within the lung. The early stage of infection, while the virus is confined to the lung mucosa, provides the ideal window of opportunity for an effective immune response to control the infection. Tissue-resident memory (Trm) CD8 T cells, located in a variety of tissues including the lung, are ideally situated to act during this window and stall the infection. The factors involved in the differentiation of lung Trm cells remain poorly defined. We demonstrate that recognition of antigen presented locally by dendritic cells (DCs) and transforming growth factor-β (TGFβ) signaling are both required. We exploited this knowledge to develop an antibody-targeted vaccination approach to generate lung Trm cells. Delivering antigen exclusively to respiratory DCs results in the development of lung CD8 Trm cells that are highly protective against lethal influenza challenge. Our results describe an effective vaccination strategy that protects against influenza virus infection.
Publisher: The American Association of Immunologists
Date: 11-2007
DOI: 10.4049/JIMMUNOL.179.9.5678
Abstract: Systemic delivery of Ag usually induces poor mucosal immunity. To improve the CD8 T cell response at mucosal sites, we targeted the Ag to MAdCAM-1, a mucosal addressin cell adhesion molecule expressed mainly by high endothelial venules (HEV) in mesenteric lymph nodes (MLN) and Peyer’s patches of gut-associated lymphoid tissue. When chemical conjugates of anti-MAdCAM-1 Ab and model Ag OVA were injected i.v., a greatly enhanced proliferative response of Ag-specific OT-I CD8 T cells was detected in MLN. This was preceded by prolonged accumulation, up to 2 wk, of the anti-MAdCAM OVA conjugate on HEV of Peyer’s patches and MLN. In contrast, nontargeted OVA conjugate was very inefficient in inducing OT-I CD8 T cell proliferation in MLN and required at least 20-fold more Ag to induce a comparable response. In addition, MAdCAM targeting elicits an endogenous OVA-specific CD8 T cell response, evident by IFN-γ production and target killing. Induced response offers protection against an OVA-expressing B cell lymphoma. We propose that the augmentation of gut CD8 T cell responses by MAdCAM targeting is due to both accumulation of Ag in the HEV and conversion of a soluble Ag to a cell-associated one, allowing cross-presentation by DCs.
Publisher: Informa UK Limited
Date: 03-2013
DOI: 10.4161/ONCI.23128
Publisher: American Thoracic Society
Date: 11-1998
DOI: 10.1165/AJRCMB.19.5.3257M
Abstract: Malignant mesothelioma (MM) is a fatal solid tumor of the mesothelium for which there is currently no ameliorating treatment. Using our murine model of this malignancy, which closely resembles the human disease, we have shown that immunotherapy may be of value in the treatment of MM. Because recombinant interleukin-12 (rIL-12) has strong immunomodulatory effects in vivo, we studied the effects of rIL-12 on murine antitumor immune responses, using a nonimmunogenic murine MM tumor cell line (AB1) in vivo. Systemic administration of rIL-12 at the time of tumor inoculation prevented AB1 tumor growth in up to 70% of treated mice, 50% of which were still resistant to AB1 upon rechallenge, indicating that long-term immunologic antitumor effects had been established. This rIL-12-induced effect was dependent on the involvement of both CD4(+) and CD8(+) but not natural killer (NK) cells. Importantly, treatment of established tumors with intralesional injections of rIL-12 resulted in temporary tumor regression or growth inhibition. This effect was dependent on the continuous presence of rIL-12 and correlated with increased numbers of CD4(+) and CD8(+) cells infiltrating the remaining tumor mass. Effective inhibition of tumor growth also occurred when IL-12 was released within MM tumors by coadministration of MM cells that had been stably transfected with the gene for IL-12. These data indicate that IL-12 has potential in the immunotherapy of MM, through gene transfer or local cytokine administration, provided that significant intratumor levels of IL-12 can be achieved for prolonged periods.
Publisher: The American Association of Immunologists
Date: 04-2017
Abstract: Nucleotide-binding and oligomerization domain (NOD)–like receptors NOD1 and NOD2 are cytosolic innate immune receptors that recognize microbial peptidoglycans. Although studies have addressed the role of NOD proteins in innate immune responses, little attention has been given to their impact on the developing adaptive immune system. We have assessed the roles of NOD1 and NOD2 deficiency on T cell development in mice. Our results demonstrate that NOD1 and NOD2 promote the positive selection/maturation of CD8 single-positive thymocytes in a thymocyte-intrinsic manner. TCR-mediated ERK phosphorylation is significantly reduced in the absence of NOD proteins, but receptor-interacting protein 2 is not involved in CD8 single-positive thymocyte selection or ERK signaling. Commensal bacteria–free animals have thymocyte maturation defects, and exogenous NOD ligands can enhance thymocyte maturation in culture. These results raise the intriguing possibility that abnormal lymphocyte responses observed in NOD-dependent inflammatory diseases are not driven solely by microbial signals in the gut, but may also involve intrinsic lymphocyte defects resulting from impaired CD8 T cell thymic development.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 26-06-2020
DOI: 10.1126/SCIIMMUNOL.AAZ8035
Abstract: Glycolipid-peptide conjugate vaccines protect against rodent malaria by generating large numbers of liver CD8 + T RM cells.
Publisher: The American Association of Immunologists
Date: 03-2009
Abstract: Dendritic cells (DCs) are extremely heterogeneous, most evident in the skin where a variety of different subsets have been identified in recent years. DCs of healthy skin include a number of distinct populations in the dermal layer as well as the well-characterized Langerhans cells (LCs) of the epidermis. These steady-state populations are augmented during bouts of local inflammation by additional monocyte-derived DCs. In an effort to better understand the distinction between the different subsets, we examined their behavior following skin infection with HSV. LC emigration rapidly followed appearance of virus in the skin and resulted in depopulation of regions in areas surrounding infected nerve endings. A separate DC population was found to accumulate within the dermis under patches of active epidermal infection with at least some derived from blood monocyte precursors. Ag-positive DCs could occasionally be found in these dermal accumulations, although they represented a minority of DCs in these areas. In addition, infected DCs appeared compromised in their trafficking capabilities and were largely absent from the migrating population. On resolution of skin disease, LCs repopulated the reformed epidermis and these were of mixed origin, with around half entering from the circulation and the remainder derived from local progenitors. Overall, our results show a range of migrational complexities between distinct skin DC populations as a consequence of localized infection.
Publisher: Proceedings of the National Academy of Sciences
Date: 24-01-2011
Abstract: Improved protein-based vaccines should facilitate the goal of effective vaccines against HIV and other pathogens. With respect to T cells, the efficiency of immunization, or “immunogenicity,” is improved by targeting vaccine proteins to maturing dendritic cells (DCs) within mAbs to DC receptors. Here, we compared the capacity of Langerin/CD207, DEC205/CD205, and Clec9A receptors, each expressed on the CD8 + DC subset in mice, to bring about immunization of microbial-specific T cells from the polyclonal repertoire, using HIV gag-p24 protein as an antigen. α-Langerin mAb targeted splenic CD8 + DCs selectively in vivo, whereas α-DEC205 and α-Clec9A mAbs targeted additional cell types. When the mAb heavy chains were engineered to express gag-p24, the α-Langerin, α-DEC205, and α-Clec9A fusion mAbs given along with a maturation stimulus induced comparable levels of gag-specific T helper 1 (Th1) and CD8 + T cells in BALB/c × C57BL/6 F1 mice. These immune T cells were more numerous than targeting the CD8 − DC subset with α-DCIR2-gag-p24. In an in vivo assay in which gag-primed T cells were used to report the early stages of T-cell responses, α-Langerin, α-DEC205, and α-Clec9A also mediated cross-presentation to primed CD8 + T cells if, in parallel to antigen uptake, the DCs were stimulated with α-CD40. α-Langerin, α-DEC205, and α-Clec9A targeting greatly enhanced T-cell immunization relative to nonbinding control mAb or nontargeted HIV gag-p24 protein. Therefore, when the appropriate subset of DCs is targeted with a vaccine protein, several different receptors expressed by that subset are able to initiate combined Th1 and CD8 + immunity.
Publisher: The American Association of Immunologists
Date: 10-2001
DOI: 10.4049/JIMMUNOL.167.7.3570
Abstract: A novel dendritic cell (DC) surface molecule termed F4/80-like-receptor (FIRE) has been selected based on its differential expression between DC subsets. The gene encoding FIRE has been cloned and sequenced, and mAbs specific for FIRE have been produced. FIRE is a seven-transmembrane-spanning molecule with two epidermal growth factor-like domains in the extracellular region. It is a novel member of the epidermal growth factor/transmembrane-7 protein subfamily and shows similarity to the macrophage marker F4/80. FIRE is expressed by CD8− DC, but not by CD8+ DC, and it is down-regulated on DC activation. It is expressed by blood monocytes and by some tissue macrophages, but not by most macrophage cell lines or by lymphoid cells. FIRE is a useful marker of myeloid cells with a DC developmental potential.
Publisher: Springer Science and Business Media LLC
Date: 17-03-2013
DOI: 10.1038/NI.2555
Abstract: Spleen-resident dendritic cell (DC) populations occupy sentinel positions for the capture and presentation of blood-borne antigens. Here we found a difference in expression of the chemotactic receptor EBI2 (GPR183) on splenic DC subsets and that EBI2 regulated the positioning and homeostasis of DCs in the spleen. EBI2 and its main ligand, 7α,25-OHC, were required for the generation of the splenic CD4(+) DC subset and the localization of DCs in bridging channels. Absence of EBI2 from DCs resulted in defects in both the activation of CD4(+) T cells and the induction of antibody responses. Regulated expression of EBI2 on DC populations is therefore critical for the generation and correct positioning of splenic DCs and the initiation of immune responses.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 11-02-2022
Abstract: Marginal zone (MZ) B cells produce broad-spectrum antibodies that protect against infection early in life. In some instances, antibody production requires MZ B cells to display pathogen antigens bound to major histocompatibility complex class II (MHC II) molecules to T cells. We describe the trogocytic acquisition of these molecules from conventional dendritic cells (cDCs). Complement component 3 (C3) binds to murine and human MHC II on cDCs. MZ B cells recognize C3 with complement receptor 2 (CR2) and trogocytose the MHC II–C3 complexes, which become exposed on their cell surface. The ubiquitin ligase MARCH1 limits the number of MHC II–C3 complexes displayed on cDCs to prevent their elimination through excessive trogocytosis. Capture of C3 by MHC II thus enables the transfer of cDC-like properties to MZ B cells.
Publisher: Frontiers Media SA
Date: 2012
Publisher: American Thoracic Society
Date: 09-1999
Abstract: Malignant mesothelioma (MM) is a solid tumor of the mesothelium for which there is no curative treatment. MM appears to be sensitive to immunotherapeutic approaches, and one of the most powerful immunomodulatory cytokines with antitumor effects is interleukin (IL)-12. We have previously shown in a murine model of MM that systemic administration of recombinant IL-12 induces a potent anti-MM immune response. The nature and accessibility of MM tumors means that they are suitable candidates for direct cytokine and gene-transfer therapeutic approaches. Therefore, we undertook a study to assess the antitumor effects induced by the local production of IL-12 within MM tumors by transfecting a murine MM line with the genes for IL-12. The IL-12 transfectant (AB1-IL-12) did not produce tumors in normal mice, but did so in athymic nude mice, implicating T cells in the prevention of MM tumor growth. In mixing experiments, paracrine IL-12 production inhibited growth of untransfected MM cells provided that cells producing IL-12 represented more than 50-80% of the inoculum. Furthermore, BALB/c mice previously challenged with AB1-IL-12 were protected against rechallenge with parental AB1 tumor, indicating that the transfectant induced long-term immunity. AB1-IL-12 induced systemic immunity that was effective at reducing the incidence of parental AB1 tumor at a distal site, but its effects were dose-dependent. Though both CD4(+) and CD8(+) cells infiltrated the rejecting tumor, CD8(+) effector cells were essential for protection against development of parental AB1 tumor. This study shows that paracrine secretion of IL-12, generated by gene transfer, can induce immunity against MM that can act locally and also at a distant site. In addition, there was no evidence of toxicity, which has been associated with the systemic administration of IL-12, indicating that this cytokine is a good candidate for experimental gene therapy in MM.
Publisher: Informa UK Limited
Date: 02-2013
DOI: 10.4161/HV.22487
Publisher: Elsevier BV
Date: 02-2012
DOI: 10.1016/J.MOLIMM.2011.11.008
Abstract: Injection of antigens coupled to antibodies against the dendritic cell (DC) surface molecule Clec9A has been shown to produce strongly enhanced antibody responses even without co-administration of adjuvants, via antigen presentation by DC on MHC class II and consequent production of follicular helper T cells. A series of mutant mice were tested to determine the DC subtypes responsible for this MHC II presentation of targeted antigen, compared to presentation of antigen on MHC I. A new clec9A null mouse was developed these mice did not give enhanced antibody production, confirming the response was dependent on Clec9A-expressing DC. However targeting of antigen to Clec9A in batf3 null mice produced enhanced antibody responses despite the marked reduction in CD8(+) DC, the major Clec9A-expressing DC subtype. This was shown to be dependent on efficient MHC II presentation by minor Clec9A-expressing DC subtypes in the environment of the Batf3(-/-) mice, namely early cells of the CD8 DC lineage and the plasmacytoid-related CD8(+) DC subset, but not by plasmacytoid cells themselves. However in normal mice most MHC II presentation of the Clec9A-targeted antigen was by the major CD8(+) DC population, the DC also responsible for presentation on MHC I.
Publisher: The American Association of Immunologists
Date: 15-06-2009
Abstract: We have cloned the mouse and human C-type lectin Clec12A, expressed both, and produced mAb recognizing both. Mouse Clec12A is highly expressed on splenic CD8+ dendritic cells (DC) and plasmacytoid DC. A proportion of CD8−DC also expresses lower levels of Clec12A, as do monocytes, macrophages, and B cells. Human CLEC12A, like the mouse counterpart, is expressed on blood monocytes and DC, including pDC and BDCA-3+DC, the proposed equivalent of mouse CD8+DC. To determine whether Ag targeted to Clec12A could induce immune responses, mice were injected with a rat mAb recognizing Clec12A, or a control rat mAb, then production of anti-rat Ig was measured. Anti-Clec12A mAb alone produced only moderate responses, but these were lified by coinjecting only small amounts of LPS as a DC activation agent. Furthermore, when OVA was conjugated to anti-Clec12A mAb, OVA-specific T cells were induced to proliferate. This Ag presentation to naive T cells was due to targeting conventional DC, because their ablation eliminated T cell activation. The potent Ab responses induced using microgram amounts of anti-Clec12A and minimal amounts of adjuvant demonstrate that this molecule can be used as an Ag-delivery target to enhance Ab responses to vaccines.
Publisher: Elsevier BV
Date: 04-2012
DOI: 10.1016/J.IMMUNI.2012.03.009
Abstract: The immune system must distinguish viable cells from cells damaged by physical and infective processes. The damaged cell-recognition molecule Clec9A is expressed on the surface of the mouse and human dendritic cell subsets specialized for the uptake and processing of material from dead cells. Clec9A recognizes a conserved component within nucleated and nonnucleated cells, exposed when cell membranes are damaged. We have identified this Clec9A ligand as a filamentous form of actin in association with particular actin-binding domains of cytoskeletal proteins. We have determined the crystal structure of the human CLEC9A C-type lectin domain and propose a functional dimeric structure with conserved tryptophans in the ligand recognition site. Mutation of these residues ablated CLEC9A binding to damaged cells and to the isolated ligand complexes. We propose that Clec9A provides targeted recruitment of the adaptive immune system during infection and can also be utilized to enhance immune responses generated by vaccines.
Publisher: Wiley
Date: 06-1999
DOI: 10.1111/J.1600-065X.1999.TB01303.X
Abstract: Self antigens can induce T-cell tolerance via a mechanism termed cross-tolerance. This involves the transfer of peripheral tissue antigens to professional APC for presentation in the draining lymph nodes. In this site, CD8+ T cells are activated, proliferate, and are slowly deleted by a CD95-dependent mechanism. Prior to their deletion, some activated cells leave the lymph nodes and encounter antigens on peripheral parenchymal tissues. Without functional CD30, these cells proliferate extensively and cause substantial tissue damage. Thus, CD30 limits autoreactivity, acting as a 'brake' on T-cell proliferation after recognition of autoantigens on parenchymal tissues.
Publisher: Wiley
Date: 14-01-2015
Abstract: Targeting antigens to dendritic cell (DC) surface receptors using antibodies has been successfully used to generate strong immune responses and is currently in clinical trials for cancer immunotherapy. Whilst cancer immunotherapy focuses on the induction of CD8(+) T-cell responses, many successful vaccines to pathogens or their toxins utilize humoral immunity as the primary effector mechanism. Universally, these approaches have used adjuvants or pathogen material that augment humoral responses. However, adjuvants are associated with safety issues. One approach, successfully used in the mouse, to generate strong humoral responses in the absence of adjuvant is to target antigen to Clec9A, also known as DNGR-1, a receptor on CD8α(+) DCs. Here, we address two issues relating to clinical application. First, we address the issue of variable adjuvant-dependence for different antibodies targeting mouse Clec9A. We show that multiple sites on Clec9A can be successfully targeted, but that strong in vivo binding and provision of suitable helper T cell determinants was essential for efficacy. Second, we show that induction of humoral immunity to CLEC9A-targeted antigens is extremely effective in nonhuman primates, in an adjuvant-free setting. Our findings support extending this vaccination approach to humans and offer important insights into targeting design.
Publisher: The American Association of Immunologists
Date: 07-2006
DOI: 10.4049/JIMMUNOL.177.1.372
Abstract: A normalized subtracted gene expression library was generated from freshly isolated mouse dendritic cells (DC) of all subtypes, then used to construct cDNA microarrays. The gene expression profiles of the three splenic conventional DC (cDC) subsets were compared by microarray hybridization and two genes encoding signal regulatory protein β (Sirpβ1 and Sirpβ4) molecules were identified as differentially expressed in CD8− cDC. Genomic sequence analysis revealed a third Sirpβ member localized in the same gene cluster. These Sirpβ genes encode cell surface molecules containing extracellular Ig domains and short intracytoplasmic domains that have a charged amino acid in the transmembrane region which can potentially interact with ITAM-bearing molecules to mediate signaling. Indeed, we demonstrated interactions between Sirpβ1 and β2 with the ITAM-bearing signaling molecule Dap12. Real-time PCR analysis showed that all three Sirpβ genes were expressed by CD8− cDC, but not by CD8+ cDC or plasmacytoid pre-DC. The related Sirpα gene showed a similar expression profile on cDC subtypes but was also expressed by plasmacytoid pre-DC. The differential expression of Sirpα and Sirpβ1 molecules on DC was confirmed by staining with mAbs, including a new mAb recognizing Sirpβ1. Cross-linking of Sirpβ1 on DC resulted in a reduction in phagocytosis of Leishmania major parasites, but did not affect phagocytosis of latex beads, perhaps indicating that the regulation of phagocytosis by Sirpβ1 is a ligand-dependent interaction. Thus, we postulate that the differential expression of these molecules may confer the ability to regulate the phagocytosis of particular ligands to CD8− cDC.
Publisher: Rockefeller University Press
Date: 08-10-2001
Abstract: Interleukin 12 (IL-12) is a 70-kD proinflammatory cytokine produced by antigen presenting cells that is essential for the induction of T helper type 1 development. It comprises 35-kD (p35) and 40-kD (p40) polypeptides encoded by separate genes that are induced by a range of stimuli that include lipopolysaccharide (LPS), DNA, and CD40 ligand. To date, the regulation of IL-12 expression at the transcriptional level has mainly been examined in macrophages and restricted almost exclusively to the p40 gene. Here we show that in CD8+ dendritic cells, major producers of IL-12 p70, the Rel/nuclear factor (NF)-κB signaling pathway is necessary for the induction of IL-12 in response to microbial stimuli. In contrast to macrophages which require c-Rel for p40 transcription, in CD8+ dendritic cells, the induced expression of p35 rather than p40 by inactivated Staphylococcus aureus, DNA, or LPS is c-Rel dependent and regulated directly by c-Rel complexes binding to the p35 promoter. This data establishes the IL-12 p35 gene as a new target of c-Rel and shows that the regulation of IL-12 p70 expression at the transcriptional level by Rel/NF-κB is controlled through both the p35 and p40 genes in a cell type–specific fashion.
Publisher: Rockefeller University Press
Date: 18-11-2002
DOI: 10.1084/JEM.20021031
Abstract: The CD45RAhiCD11cint plasmacytoid predendritic cells (p-preDCs) of mouse lymphoid organs, when stimulated in culture with CpG or influenza virus, produce large amounts of type I interferons and transform without ision into CD8+CD205− DCs. P-preDCs express CIRE, the murine equivalent of DC-specific intercellular adhesion molecule 3 grabbing nonintegrin (DC-SIGN). P-preDCs are isible by CD4 expression into two subgroups differing in turnover rate and in response to Staphylococcus aureus. The kinetics of bromodeoxyuridine labeling and the results of transfer to normal recipient mice indicate that CD4− p-preDCs are the immediate precursors of CD4+ p-preDCs. Similar experiments indicate that p-preDCs are normally long lived and are not the precursors of the short-lived steady-state conventional DCs. However, in line with the culture studies on transfer to influenza virus-stimulated mice the p-preDCs transform into CD8+CD205− DCs, distinct from conventional CD8+CD205+ DCs. Hence as well as activating preexistant DCs, microbial infection induces a wave of production of a new DC subtype. The functional implications of this shift in the DC network remain to be determined.
Publisher: Elsevier BV
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 19-07-2013
DOI: 10.1038/NI0813-876E
No related grants have been discovered for Irina Caminschi.