ORCID Profile
0000-0002-9624-4370
Current Organisations
Charles Sturt University
,
Charles Sturt University - Orange Campus
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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.
Veterinary Microbiology (excl. Virology) | Animal Production | Animal Protection (Pests and Pathogens) | Infectious Agents | Food Packaging, Preservation and Safety |
Poultry | Veterinary Biological Preventatives (e.g. Vaccines) | Expanding Knowledge in the Agricultural and Veterinary Sciences
Publisher: BMJ
Date: 16-04-2008
Publisher: Wiley
Date: 12-1996
DOI: 10.1111/J.1751-0813.1996.TB07568.X
Abstract: To compare the effects of two oil emulsion adjuvants (incomplete Freunds adjuvant and a proprietary oil adjuvant), DEAE-dextran, L-tyrosine particles and Quil A on the humoral immune responses of sheep immunised with recombinant pili of Dichelobacter Nodosus (strain A). Antibody titres were studied for up to 32 weeks and were measured by bacterial agglutination and ELISA. The relative avidity of antibodies for pili was determined and the incidence and severity of adverse reactions at the site of injection of vaccines were recorded. The oil emulsion adjuvants and Quil A were more effective than either DEAE-dextran or L-tyrosine at stimulating antibodies in sheep. The incidence and severity of adverse reactions was lower in sheep which received vaccines containing either Quil A or DEAE-dextran than in sheep which received vaccines containing oil emulsion adjuvants. L-tyrosine had no adverse effects. Quil A was as effective as oil adjuvants at stimulating high levels of antibodies against recombinant pili in sheep and had the significant advantage of being less irritant after subcutaneous injection.
Publisher: Elsevier BV
Date: 12-2010
Publisher: American Physical Society (APS)
Date: 06-08-2004
Publisher: Elsevier BV
Date: 04-2018
Publisher: Informa UK Limited
Date: 2003
Publisher: Elsevier BV
Date: 09-2005
DOI: 10.1016/J.IJMM.2005.06.005
Abstract: An effective vaccine would be a desirable way to control Helicobacter pylori-induced gastric disease. Initial studies in animal models demonstrated the feasibility of immunization and led to high hopes for a human vaccine. In the mouse model immunological approaches have to date not brought a satisfactory explanation for the mechanisms of protection against this largely luminal pathogen. Recently, transcriptome studies have identified new factors. It is now proposed that non-classical immune mediators may be the key to vaccine-induced protection. Human trials of H. pylori vaccines are going ahead but although at least some formulations are clearly immunogenic, their effectiveness remains untested. The recent development of a human challenge model has now opened up new prospects for testing candidate vaccines and this will undoubtedly have a great impact in the near future. Future priorities for H. pylori vaccine development must be a better understanding of the protective mechanisms and the identification of biomarkers which can be used as reliable predictors of efficacy in humans. Despite some important advances in recent years, important issues must be resolved before an H. pylori vaccine will become a reality.
Publisher: MDPI AG
Date: 21-09-2020
Abstract: There is a growing demand for better delivery systems to improve the stability and efficacy of DNA vaccines. Here we report the synthesis of a non-viral DNA vaccine delivery system using a novel adjuvanted solid lipid nanoparticle (SLN-A) platform as a carrier for a DNA vaccine candidate encoding the Urease alpha (UreA) antigen from Helicobacter pylori. Cationic SLN-A particles containing monophosphoryl lipid A (adjuvant) were synthesised by a modified solvent-emulsification method and were investigated for their morphology, zeta potential and in vitro transfection capacity. Particles were found to bind plasmid DNA to form lipoplexes, which were characterised by electron microscopy, dynamic light scattering and fluorescence microscopy. Cellular uptake studies confirmed particle uptake within 3 h, and intracellular localisation within endosomal compartments. In vitro studies further confirmed the ability of SLN-A particles to stimulate expression of pro-inflammatory cytokine tumor necrosis factor alpha (TNF-α) in human macrophage-like Tohoku Hospital Pediatrics-1 (THP-1) cells. Lipoplexes were found to be biocompatible and could be efficiently transfected in murine immune cells for expression of recombinant H. pylori antigen Urease A, demonstrating their potential as a DNA vaccine delivery system.
Publisher: Wiley
Date: 03-11-2003
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0RA06120D
Abstract: We report a novel cubosome formulation that is effective at killing Staphylococcus aureus in vitro .
Publisher: American Society for Microbiology
Date: 02-2013
DOI: 10.1128/IAI.00930-12
Abstract: Bacterial infections are a common and serious complication of type 2 diabetes (T2D). The prevalence of melioidosis, an emerging tropical infection caused by the Gram-negative bacterium Burkholderia pseudomallei , is increased in people with T2D. This is the first study to compare murine models of T2D and melioidosis. Susceptibility and disease progression following infection with B. pseudomallei were compared in our diet-induced polygenic mouse model and a leptin receptor-deficient monogenic model of T2D. The metabolic profile of mice with diet-induced diabetes, including body weight, blood glucose, cholesterol, triglycerides, insulin resistance, and baseline levels of inflammation, closely resembled that of clinical T2D. Following subcutaneous infection with B. pseudomallei , bacterial loads at 24 and 72 h postinfection in the blood, spleen, liver, lungs, and subcutaneous adipose tissue (SAT) at the site of infection were compared in parallel with the expression of inflammatory cytokines and tissue histology. As early as 24 h postinfection, the expression of inflammatory (interleukin-1β [IL-1β], tumor necrosis factor alpha [TNF-α], and IL-6) and T H 1 (IL-12 and gamma interferon [IFN-γ]) cytokines was impaired in diabetic mice compared to nondiabetic littermates. Early differences in cytokine expression were associated with excessive infiltration of polymorphonuclear neutrophils (PMN) in diabetic mice compared to nondiabetic littermates. This was accompanied by bacteremia, hematogenous dissemination of bacteria to the lungs, and uncontrolled bacterial growth in the spleens of diabetic mice by 72 h postinfection. The findings from our novel model of T2D and melioidosis comorbidity support the role of impaired early immune pathways in the increased susceptibility of in iduals with T2D to bacterial infections.
Publisher: American Physical Society (APS)
Date: 23-09-2004
Publisher: American Physical Society (APS)
Date: 22-09-2004
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.VACCINE.2022.08.059
Abstract: Vaccines are very effective in providing protection against many infectious diseases. However, it has proven difficult to develop highly efficacious vaccines against some pathogens and so there is a continuing need to improve vaccine technologies. The first successful and widely used vaccines were based on attenuated pathogens (e.g., laboratory passaged Pasteurella multocida to vaccinate against fowl cholera) or closely related non-pathogenic organisms (e.g., cowpox to vaccinate against smallpox). Subsequently, live vaccines, either attenuated pathogens or non-pathogenic microorganisms modified to deliver heterologous antigens, have been successfully used to induce protective immune responses against many pathogens. Unlike conventional killed and subunit vaccines, live vaccines can deliver antigens to mucosal surfaces in a similar manner and context as the natural infection and hence can often produce a more appropriate and protective immune response. Despite these advantages, there is still a need to improve the immunogenicity of some live vaccines. The efficacy of injectable killed and subunit vaccines is usually enhanced using adjuvants such mineral salts, oils, and saponin, but such adjuvants cannot be used with live vaccines. Instead, live vaccines can be engineered to produce immunomodulatory molecules that can stimulate the immune system to induce more robust and long-lasting adaptive immune responses. This review focuses on research that has been undertaken to engineer live vaccines to produce immunomodulatory molecules that act as adjuvants to increase immunogenicity. Adjuvant strategies with varying mechanisms of action (inflammatory, antibody-mediated, cell-mediated) and delivery modes (oral, intramuscular, intranasal) have been investigated, with varying degrees of success. The goal of such research is to define adjuvant strategies that can be adapted to enhance live vaccine efficacy by triggering strong innate and adaptive immune responses and produce vaccines against a wider range of pathogens.
Publisher: Elsevier BV
Date: 05-2000
DOI: 10.1016/S0020-7519(00)00043-6
Abstract: The histones of Plasmodium falciparum represent a potential new target for anti-malarial compounds. A naturally occurring compound, apicidin, has recently been shown to inhibit the in vitro growth of P. falciparum. Apicidin was shown to hyperacetylate histones, suggesting that its mode of action is through histone deacetylase inhibition. We have tested the ability of known histone deacetylase inhibitors, mammalian tumour suppressor compounds, and cytodifferentiating agents to inhibit the in vitro growth of a drug sensitive and resistant strain of P. falciparum. Seven of the tested compounds had microM IC50 values, and trichostatin A, a histone deacetylation inhibitor and cytodifferentiating agent, was active at low nM concentrations. One compound, suberic acid bisdimethylamide, which selectively arrests tumour cells as opposed to normal mammalian cells, had an in vivo cytostatic effect against the acute murine malaria Plasmodium berghei, and one round of treatment with the compound failed to select for resistant mutations. These results suggest a promising role for histone deacetylase inhibitors and cytodifferentiating agents as antimalarial drug candidates.
Publisher: American Physical Society (APS)
Date: 10-09-2003
Publisher: Elsevier BV
Date: 04-2010
DOI: 10.1016/J.IJPARA.2009.10.008
Abstract: Immunohistochemistry, confocal immunofluorescence and immunogold labelling were used to determine the localisation of the host-protective antigens To16, To18 and To45W in Taenia ovis oncospheres. During maturation of the adult tapeworm the antigens were initially seen as diffuse staining in the developing oncospheres but in mature oncospheres four distinct cells stained positively for the antigens. Confocal fluorescence microscopy using different fluorophores revealed that each of the antigens co-localises within the same cells in the oncosphere. No surface localisation was seen in non-activated or recently activated parasites. Immunogold labelling of non-activated oncosphere sections viewed in transmission electron microscopy revealed labelling of bilateral cells, however the identities of these cells was unclear due to deficiencies in the current level of understanding of oncosphere ultrastructure. Localisation of all the antigens changed dramatically after oncospheres were activated in vitro with each of the antigens being dispersed more generally throughout the parasite parenchyma. During development of the parasites in in vitro culture, surface localisation of the proteins was seen in parasites after 3 or more days in culture. All three antigens were found to be completely absent in parasites by 15 days of culture. The location of the host-protective antigens suggests that initially the invading oncospheres are not susceptible to vaccine-induced antibody and complement mediated attack, but that as the parasites mature, the host-protective antigens come to be associated with the parasite's surface, rendering them susceptible to immune attack.
Publisher: American Physical Society (APS)
Date: 10-12-2003
Publisher: Cambridge University Press (CUP)
Date: 21-07-2010
DOI: 10.1017/S0031182010001034
Abstract: Immunohistochemistry and immunogold labelling techniques were used to localize the EG95 vaccine antigen in Echinococcus granulosus oncospheres. In non-activated oncospheres, the cytoplasm of 2 pairs of bilateral cells exhibited specific positive labelling for the presence of EG95. No surface localization was seen in non-activated or recently activated oncospheres. Besides the staining of 2 pairs of bilateral cells, there was also a generalized distribution of specific staining for EG95 throughout the parenchyma of activated oncospheres. Immunogold labelling of non-activated oncosphere revealed specific reactivity for EG95 involving 2 pairs of bilateral cells and the ultrastructural characteristics of these cells were consistent with them being penetration gland cells. No other oncospheral structures stained specifically for the presence of EG95. The absence of surface location of EG95 in oncospheres suggests that the parasite may not be susceptible to vaccine-induced antibody and complement mediated attack until some post-oncospheral development has occurred. Further studies would be required to determine when the EG95 antigen associates with the parasite's surface, thus making them susceptible to immune attack.
Publisher: Elsevier BV
Date: 2008
DOI: 10.1016/J.IJMM.2007.07.009
Abstract: Helicobacter pylori infection remains a significant global public health problem. Vaccine development against this infection appears to be feasible but has not yet delivered its promise in clinical trials. Efforts to improve current vaccination strategies would greatly benefit from a better molecular understanding of the mechanism of protection. Here, we review recent developments in this field.
Publisher: Frontiers Media SA
Date: 03-07-2023
Publisher: Informa UK Limited
Date: 04-2010
Publisher: Elsevier BV
Date: 02-1998
DOI: 10.1016/S0168-3659(97)00180-6
Abstract: Biodegradable implants made from cholesterol and lecithin (C:L) were used to deliver a recombinant antigen (recombinant Dichelobacter nodosus pili) and adjuvant (Quil A) to sheep. Implants (5.5- x 1.8-mm) were placed subcutaneously and compared to a conventional vaccination regime (2 injections, 4 weeks apart) for antibody responses and tissue compatibility. Release profiles of antigen and adjuvant were also studied in vitro and in vivo. The presence of Quil A in vaccine implants had a marked effect on the rate at which antigen was released with 29 and 44% being released in the first 24 h from implants containing pili alone and pili with Quil A, respectively. Sheep produced significant levels of antibody when immunized with implants, however the response was short-lived and of significantly lower intensity than the response stimulated by two injections of antigen with Quil A (P < 0.01). A second implant system was developed where implants coated with C:L to delay antigen release, were used in combination with uncoated implants to deliver a priming dose and boosting dose of antigen. Antibody titres stimulated by the 4 double implant system were equivalent to those stimulated by a conventional regime of two injections (four weeks apart) for the first six weeks of the experiment. After this time, antibody levels in the groups which received implants dropped significantly. In vitro studies revealed that some of the implant coatings had caused a delay in the release of antigen (the rate of release peaked at 72 h), however this was not long enough to provide a significant boosting effect. In all cases, implants were well tolerated by sheep and caused less local reaction than injected vaccines.
Publisher: American Physical Society (APS)
Date: 13-07-2004
Publisher: Springer International Publishing
Date: 2016
DOI: 10.1007/978-3-319-27592-5_19
Abstract: Changes in diet are a challenge to the gastrointestinal tract which needs to alter its processing mechanisms to continue to process nutrients and maintain health. In particular, the enteric nervous system (ENS) needs to adapt its motor and secretory programs to deal with changes in nutrient type and load in order to optimise nutrient absorption.The nerve circuits in the gut are complex, and the numbers and types of neurons make recordings of specific cell types difficult, time-consuming, and prone to s ling errors. Nonetheless, traditional research methods like intracellular electrophysiological approaches have provided the basis for our understanding of the ENS circuitry. In particular, animal models of intestinal inflammation have shown us that we can document changes to neuronal excitability and synaptic transmission.Recent studies examining diet-induced changes to ENS programming have opted to use fast imaging techniques to reveal changes in neuron function. Advances in imaging techniques using voltage- or calcium-sensitive dyes to record neuronal activity promise to overcome many limitations inherent to electrophysiological approaches. Imaging techniques allow access to a wide range of ENS phenotypes and to the changes they undergo during dietary challenges. These sorts of studies have shown that dietary variation or obesity can change how the ENS processes information-in effect reprogramming the ENS. In this review, the data gathered from intracellular recordings will be compared with measurements made using imaging techniques in an effort to determine if the lessons learnt from inflammatory changes are relevant to the understanding of diet-induced reprogramming.
Publisher: American Physiological Society
Date: 2015
Abstract: The trefoil factor TFF2 is a member of a tripartite family of small proteins that is produced by the stomach and the colon. Recombinant TFF2, when applied intrarectally in a rodent model of hapten colitis, hastens mucosal healing and reduces inflammatory indexes. Additionally, TFF2 is expressed in immune organs, supporting a potential immunomodulatory and reparative role in the bowel. In this study we confirm that TFF2 is expressed in the colon and is specifically enriched in epithelial cells relative to colonic leukocytes. TFF2-deficient, but not TFF1-deficient, mice exhibit a more severe response to acute or chronic dextran sulfate (DSS)-induced colitis that correlates with a 50% loss of expression of TFF3, the principal colonic trefoil. In addition, the response to acute colitis is associated with altered expression of IL-6 and IL-33, but not other inflammatory cytokines. While TFF2 can reduce macrophage responsiveness and block inflammatory cell recruitment to the colon, the major role in limiting the susceptibility to acute colitis appears to be maintenance of barrier function. Bone marrow transfer experiments demonstrate that leukocyte expression of TFF2 is not sufficient for prevention of colitis induction but, rather, that the gastrointestinal epithelium is the primary source of TFF2. Together, these findings illustrate that epithelial TFF2 is an important endogenous regulator of gut mucosal homeostasis that can modulate immune and epithelial compartments. Because of its extreme stability, even in the corrosive gut lumen, TFF2 is an attractive candidate as an oral therapeutic scaffold for future drug development in the treatment of inflammatory bowel disease.
Publisher: Wiley
Date: 22-02-2012
DOI: 10.1111/J.1440-1681.2011.05657.X
Abstract: NADPH oxidases (Nox) are reactive oxygen species (ROS)-generating enzymes that play important physiological roles in host defence and redox signalling. However, Nox activity is upregulated in the vascular wall during atherosclerosis and contributes to plaque formation by promoting oxidative stress and inflammation. The bacterium Chlamydia pneumoniae has been detected in vascular smooth muscle cells (VSMC) of human atheroma. We hypothesized that C. pneumoniae infection of VSMC causes Nox activation, which initially limits infection but ultimately causes oxidative stress, activation of pro-inflammatory pathways and an atherogenic phenotype. Chlamydia pneumoniae infection of mouse cultured VSMC significantly increased ROS production by twofold but did not upregulate mRNA expression of Nox1 or Nox4. Chlamydia pneumoniae did increase Nox2 mRNA levels significantly by threefold, but this did not translate to elevated Nox2 protein expression. The Nox inhibitor gp91ds-tat had no effect on C. pneumoniae-induced ROS production. In contrast, apocynin significantly reduced ROS levels by 75% in C. pneumoniae-infected VSMC, an effect most likely attributable to its direct anti-oxidant action. Although apocynin had no effect on C. pneumoniae-induced expression of inflammatory markers, bacteria recovered from apocynin-treated VSMC displayed a higher degree of infectivity in HEp-2 cells. In conclusion, C. pneumoniae infection increases ROS production in VSMC independently of Nox activity. Although elevated ROS production appears to serve a protective role by limiting the spread of infection, we speculate that this response will be detrimental over the long term by causing oxidative stress and a smouldering inflammatory response by maintaining C. pneumoniae persistence within the cell.
Publisher: Springer Science and Business Media LLC
Date: 30-08-2013
DOI: 10.1007/S00210-013-0909-5
Abstract: Vascular smooth muscle cells (VSMC) are present in arterial intima before atherosclerotic plaques develop and are likely to be exposed to unmodified serum lipids as they enter the vessel wall. We examined the effects of sera from mice on the morphology and function of mouse VSMC. Incubation of a mouse VSMC line (MOVAS) with sera from normocholesterolemic (C57BL/6J) or hypercholesterolemic (APOE(-/-)) mice caused concentration-dependent increases in lipid accumulation as measured by AdipoRed, with the extent of lipid uptake significantly greater with the latter sera type. Inhibition of c-Jun N-terminal kinases (SP600125), Src kinases (AG1879), and clathrin-dependent endocytosis (monodansylcadaverine) to disrupt scavenger receptor-mediated uptake of lipids had no effect on serum-induced lipid accumulation by VSMC. By contrast, inhibition of macropinocytosis with antagonists of PI-3 kinase (LY294002) and actin (cytochalasin D) markedly reduced lipid accumulation. Serum exposure reduced the expression of the ATP-binding cassette transporter A1, consistent with impaired cholesterol efflux, but had no effect on the expression of markers of VSMC differentiation. Moreover, the expression of several inflammation and foam cell markers was unchanged (CCL2, CCL5, and CD68) by mouse sera. The accumulation of unmodified serum lipids by VSMC involves a macropinocytosis-like uptake pathway and is associated with the downregulation of the ATP-binding cassette transporter. We speculate that VSMC may play an atheroprotective role in arterial intima by acting as a "sink" for unmodified lipids.
Publisher: Public Library of Science (PLoS)
Date: 13-07-2015
Publisher: Hindawi Limited
Date: 11-2003
DOI: 10.1046/J.1462-5822.2003.00324.X
Abstract: Cyclooxygenase-2 (COX-2) represents the inducible key enzyme of arachidonic acid metabolism and contributes to the pathogenesis of gastroduodenal ulcers and gastric cancer. Helicobacter pylori infection is associated with elevated gastric COX-2 levels, but the mechanisms underlying H. pylori-dependent cox-2 gene expression are unclear. H. pylori stimulated cox-2 mRNA and protein abundance in gastric epithelial cells in vitro and in vivo, and functional analysis of the cox-2 gene promoter mapped its H. pylori-responsive region to a proximal CRE/Ebox element at -56 to -48. Moreover, USF1/-2 and CREB transcription factors binding to this site were identified to transmit H. pylori-dependent cox-2 transcription. Activation of MEK/ERK1/-2 signalling by bacterial virulence factors located outside the H. pylori cag pathogenicity island (cagPAI) was found to mediate bacterial effects on the cox-2 promoter. Our study provides a detailed description of the molecular pathways underlying H. pylori-dependent cox-2 gene expression in gastric epithelial cells, and may thus contribute to a better understanding of mechanisms underlying H. pylori pathogenicity.
Publisher: American Physical Society (APS)
Date: 24-12-2003
Publisher: Hindawi Limited
Date: 05-2008
DOI: 10.1111/J.1462-5822.2007.01105.X
Abstract: Intramacrophage survival appears to be a pathogenic trait common to Salmonellae and definition of the metabolic requirements of Salmonella within macrophages might provide opportunities for novel therapeutic interventions. We show that loss of PurG function in Salmonella enterica serovar Typhimurium SL1344 leads to death of the bacterium in RAW264.7 cells, which was due to unavailability of purine nucleotides but not thiamine in the phagosome of RAW264.7 cells. Phagosomal escape of purG mutant restored growth, suggesting that the phagosomal environment, but not the cytosol, is toxic to Salmonella purine auxotrophs. NADPH oxidase inhibition restored the growth of purG mutant in RAW264.7 cells, implying that the Salmonella-containing vacuole acquires reactive oxygen species (ROS) that are lethal to purine auxotrophs. Under purine limiting conditions, purG mutant was unable to repair the damage caused by hydrogen peroxide or UV irradiation, suggesting that ROS-mediated DNA damage may have been responsible for the attenuated phenotype of purG mutant in RAW264.7 cells and in mice. These studies highlight the possibility of utilizing the Salmonella purine nucleotide biosynthetic pathway as a prospective therapeutic target and also underline the importance of metabolic pathways in assembling a comprehensive understanding of the host-pathogen interactions inside phagocytic cells.
Publisher: Wiley
Date: 07-11-2016
DOI: 10.1111/IMM.12676
Publisher: Oxford University Press (OUP)
Date: 02-2006
Publisher: American Physical Society (APS)
Date: 06-07-2004
Publisher: Wiley
Date: 22-09-2010
Abstract: Helicobacter pylori is recognised as the chief cause of chronic gastritis, ulcers and gastric cancer in humans. With increased incidence of treatment failure and antibiotic resistance, development of prophylactic or therapeutic vaccination is a desirable alternative. Although the results of vaccination studies in animal models have been promising, studies in human volunteers have revealed problems such as 'post-immunisation gastritis' and comparatively poor responses to vaccine antigens. The focus of this study was to compare the gastric and systemic cellular immune responses induced by recombinant attenuated Salmonella Typhimurium-based vaccination in the C57BL/6 model of H. pylori infection. Analysis of lymphocyte populations in the gastric mucosa, blood, spleen, paragastric LN and MLN revealed that the effects of vaccination were largely confined to the parenchymal stomach rather than lymphoid organs. Vaccine-induced protection was correlated with an augmented local recall response in the gastric mucosa, with increased proportions of CD4(+) T cells, neutrophils and reduced proportions of CD4(+) Treg. CD4(+) T cells isolated from the stomachs of vaccinated mice proliferated ex vivo in response to H. pylori antigen, and secreted Th1 cytokines, particularly IFN-γ. This detailed analysis of local gastric immune responses provides insight into the mechanism of vaccine-induced protection.
Publisher: American Physical Society (APS)
Date: 03-02-2004
Publisher: American Physical Society (APS)
Date: 11-03-2004
Publisher: American Physical Society (APS)
Date: 10-03-2004
Publisher: Elsevier BV
Date: 10-2003
Publisher: Elsevier BV
Date: 2007
DOI: 10.1016/J.JBIOTEC.2006.09.003
Abstract: Microarrays have rapidly become an indispensable tool for gene analysis. Microarray experiments can be cost prohibitive, however, largely due to the price of the arrays themselves. Whilst different methods for stripping filter arrays on membranes have been established, only very few protocols are published for thermal and chemical stripping of microarrays on glass. Most of these protocols for stripping microarrays on glass were developed in combination with specific surface chemistry and different coatings for covalently immobilizing presynthesized DNA in a deposition process. We have developed a method for stripping commercial in situ microarrays using a multi-step procedure. We present a method that uses mild chemical degradation complemented by enzymatic treatment. We took advantage of the differences in biochemical properties of covalently linked DNA oligonucleotides on in situ synthesized microarrays and the antisense cRNA hybridization probes. The success of stripping protocols for microarrays on glass was critically dependent on the type of arrays, the nature of s le used for hybridization, as well as hybridization and washing conditions. The protocol employs alkali hydrolysis of the cRNA, several enzymatic degradation steps using RNAses and Proteinase K, combined with appropriate washing steps. Stripped arrays were rehybridized using the same protocols as for new microarrays. The stripping method was validated with microarrays from different suppliers and rehybridization of stripped in situ arrays yielded comparable results to hybridizations done on unused, new arrays with no significant loss in precision or accuracy. We show that stripping of commercial in situ arrays is feasible and that reuse of stripped arrays gave similar results compared to unused ones. This was true even for biological s les that show only slight differences in their expression profiles. Our analyses indicate that the stripping procedure does not significantly influence data quality derived from post-primary hybridizations. The method is robust, easy to perform, inexpensive, and results after reuse are of comparable accuracy to new arrays.
Publisher: American Physical Society (APS)
Date: 20-10-2004
Publisher: Wiley
Date: 09-2015
DOI: 10.1111/HEL.12252
Abstract: During the last year, a variety of studies have been published that increases our understanding of the basic mechanisms of immunity and inflammation in Helicobacter pylori infection and progression to gastric cancer. Innate immune regulation and epithelial cell response were covered by several studies that contribute with new insights in the host response to H. pylori infection. Also, the adaptive immune response to H. pylori and particularly the role of IL-22 have been addressed in some studies. These advances may improve vaccine development where new strategies have been published. Two major studies analyzed H. pylori genomes of 39 worldwide strains and looked at the protein profiles. In addition, multi-epitope vaccines for therapeutic use have been investigated. Studies on different adjuvants and delivery systems have also given us new insights. This review presents articles from the last year that reveal detailed insight into immunity and regulation of inflammation, the contribution of immune cells to the development of gastric cancer, and understanding mechanisms of vaccine-induced protection.
Publisher: Springer Science and Business Media LLC
Date: 04-2005
DOI: 10.1007/S15010-005-4068-6
Abstract: Despite intensive research, the etiology of acute anterior uveitis (AAU) remains poorly defined. Infection with gram-negative bacteria such as Yersinia, Salmonella, Shigella, and Chlamydia have already been suggested as a possible trigger event for AAU. Helicobacter pylori is also a gram-negative bacterium, shares the lipopolysaccharides, but did not attract the attention of many ophthalmologists until recently. Having in mind the relatively high incidence of H. pylori infection in the population, we propose that H. pylori may also be a trigger factor for AAU. The presence of anti-H. pylori antibodies in matching serum and aqueous humor s les of 15 idiopathic AAU patients was determined using a commercial Western blot assay. Control serum and aqueous humor were obtained from five patients undergoing cataract surgery. Six out of 15 AAU patients (40%) were serum-positive for H. pylori, and half of these (n = 3) also had anti-H. pylori antibodies in the aqueous humor. All five aqueous humor and sera controls tested negative for H. pylori infection. These are the first results demonstrating anti-H. pylori antibodies in the aqueous humor of AAU patients. Further studies are needed to demonstrate whether this antibody is indeed locally produced. Our data may provide first evidence for a causative link between H. pylori infection and AAU.
Publisher: American Physical Society (APS)
Date: 25-06-2004
Publisher: Elsevier BV
Date: 07-2014
Publisher: Wiley
Date: 04-08-2010
DOI: 10.1111/J.1365-3024.2010.01230.X
Abstract: Immunohistochemistry and immunofluorescence with confocal microscopy were used to localize the host‐protective antigens of Taenia saginata (TSA9 and TSA18) and Taenia solium (TSOL16, TSOL18 and TSOL45). In nonactivated oncospheres, TSA9 and TSOL45 antigens were found primarily in the cytoplasm of the penetration gland type one (PG1) cell. A similar pattern of staining was seen for TSOL45 in oncospheres of T. solium that remained within the oncospheral membrane. In addition, there was less intense staining of TSA9 and TSOL45 in the quadri‐nucleate penetration gland type 2 (PG2) cell. TSA18, TSOL16 and TSOL18 were predominantly found in the PG2 cell. In activated oncospheres that had escaped the oncospheral membrane, the antigens (other than TSA9) were seen both in the penetration gland cell locations and throughout the oncospheral parenchyma. Co‐localization analyses revealed that only TSOL16 and TSOL18 antigens were co‐localized in the PG2 cell of oncospheres that had not escaped the oncospheral membrane. However, in activated oncospheres that escaped the oncospheral membrane, all three antigens of T. solium were co‐localized as they were present throughout the parenchyma. No positive staining was observed on the surface of nonactivated or recently activated oncospheres of T. saginata or T. solium.
Publisher: Wiley
Date: 05-04-2022
DOI: 10.1111/HEL.12891
Abstract: For decades, traditional in vitro and in vivo models used for the study of Helicobacter pylori infection have relied heavily on the use of gastric cancer cell lines and rodents. Major challenges faced by these methods have been the inability to study cancer initiation in already cancerous cell lines, and the difficulty in translating results obtained in animal models due to genetic differences. These challenges have prevented a thorough understanding of the pathogenesis of disease and slowed the development of cancer therapies and a suitable vaccine against the pathogen. In recent years, the development of gastric organoids has provided great advantages over the traditional in vivo and in vitro models due to their similarities to the human stomach in vivo , their ease of use, and the capacity for long‐term culture. This review discusses the advantages and limitations of existing in vivo and in vitro models of H . pylori infection, and how gastric organoids have been applied to study H . pylori pathogenesis, with a focus on how the pathogen interacts with the gastric epithelium, inflammatory processes, epithelial repair, and cancer initiation. The potential applications of organoids to address more complex questions on the role of hormones, vaccine‐induced immunity are also discussed.
Publisher: American Society for Microbiology
Date: 05-2008
DOI: 10.1128/IAI.01481-07
Abstract: Helicobacter pylori is the etiological agent of human chronic gastritis, a condition seen as a precursor to the development of gastrointestinal ulcers or gastric cancer. This study utilized the murine model of chronic H. pylori infection to characterize the role of macrophages in the induction of specific immune responses and gastritis and in the control of the bacterial burden following H. pylori infection and vaccination. Drug-loaded liposomes were injected intravenously to deplete macrophages from C57BL/6 mice, and effective removal of CD11b + cells from the spleens and stomachs of mice was confirmed by immunofluorescence microscopy. Transient elimination of macrophages from C57BL/6 mice during the early period of infection reduced the gastric pathology induced by H. pylori SS1 but did not affect the bacterial load in the stomach. These data suggest that macrophages are important to the severity of gastric inflammation during H. pylori infection.
Publisher: SAGE Publications
Date: 10-02-2010
Abstract: Cerebral infarct volume is typically smaller in premenopausal females than in age-matched males after ischemic stroke, but the underlying mechanisms are poorly understood. In this study we provide evidence in mice that this gender difference only occurs when the ischemic brain is reperfused. The limited tissue salvage achieved by reperfusion in male mice is associated with increased expression of proinflammatory proteins, including cyclooxygenase-2 (Cox-2), Nox2, and vascular cell adhesion molecule-1 (VCAM-1), and infiltration of Nox2-containing T lymphocytes into the infarcted brain, whereas such changes are minimal in female mice after ischemia–reperfusion (I-R). Infarct volume after I-R was no greater at 72 h than at 24 h in either gender. Infarct development was Nox2 dependent in male but not in female mice, and Nox2 within the infarct was predominantly localized in T lymphocytes. Stroke resulted in an ∼15-fold increase in Nox2-dependent superoxide production by circulating, but not spleen-derived, T lymphocytes in male mice, and this was ∼sevenfold greater than in female mice. These circulating immune cells may thus represent a major and previously unrecognized source of superoxide in the acutely ischemic and reperfused brain of males (and potentially in postmenopausal females). Our findings provide novel insights into mechanisms that could be therapeutically targeted in acute ischemic stroke patients who receive thrombolysis therapy to induce cerebral reperfusion.
Publisher: Wiley
Date: 09-09-2019
DOI: 10.1111/HEL.12658
Publisher: Springer Science and Business Media LLC
Date: 24-03-2009
Abstract: Helicobacter pylori is a crucial determining factor in the pathogenesis of benign and neoplastic gastric diseases. Cyclooxygenase-2 (Cox-2) is the inducible key enzyme of arachidonic acid metabolism and is a central mediator in inflammation and cancer. Expression of the Cox-2 gene is up-regulated in the gastric mucosa during H. pylori infection but the pathobiological consequences of this enhanced Cox-2 expression are not yet characterized. The aim of this study was to identify novel genes down-stream of Cox-2 in an in vivo model, thereby identifying potential targets for the study of the role of Cox- 2 in H. pylori pathogenesis and the initiation of pre- cancerous changes. Gene expression profiles in the gastric mucosa of mice treated with a specific Cox-2 inhibitor (NS398) or vehicle were analysed at different time points (6, 13 and 19 wk) after H. pylori infection. H. pylori infection affected the expression of 385 genes over the experimental period, including regulators of gastric physiology, proliferation, apoptosis and mucosal defence. Under conditions of Cox-2 inhibition, 160 target genes were regulated as a result of H. pylori infection. The Cox-2 dependent subset included those influencing gastric physiology ( Gastrin, Galr1 ), epithelial barrier function ( Tjp1, connexin45, Aqp5 ), inflammation ( Icam1 ), apoptosis ( Clu ) and proliferation ( Gdf3, Igf2 ). Treatment with NS398 alone caused differential expression of 140 genes, 97 of which were unique, indicating that these genes are regulated under conditions of basal Cox-2 expression. This study has identified a panel of novel Cox-2 dependent genes influenced under both normal and the inflammatory conditions induced by H. pylori infection. These data provide important new links between Cox-2 and inflammatory processes, epithelial repair and integrity.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2NR03415H
Abstract: C-dots loaded cubosome is green fluorescent for cell imaging.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-10-2010
Publisher: Frontiers Media SA
Date: 2012
Publisher: MDPI AG
Date: 03-03-2022
DOI: 10.3390/IJMS23052790
Abstract: Gastric cancer represents a significant disease burden worldwide. The factors that initiate cancer are not well understood. Chronic inflammation such as that triggered by H. pylori infection is the most significant cause of gastric cancer. In recent years, organoid cultures developed from human and animal adult stem cells have facilitated great advances in our understanding of gastric homeostasis. Organoid models are now being exploited to investigate the role of host genetics and bacterial factors on proliferation and DNA damage in gastric stem cells. The impact of a chronic inflammatory state on gastric stem cells and the stroma has been less well addressed. This review discusses what we have learned from the use of organoid models to investigate cancer initiation, and highlights questions on the contribution of the microbiota, chronic inflammatory milieu, and stromal cells that can now be addressed by more complex coculture models.
Publisher: American Society for Microbiology
Date: 10-2013
DOI: 10.1128/IAI.01424-12
Abstract: The natural immune response to Helicobacter pylori neither clears infection nor prevents reinfection. However, the ability of secretory antibodies to influence the course of H. pylori infection has not been determined. We compared the natural progression of H. pylori infection in wild-type C57BL/6 mice with that in mice lacking the polymeric immunoglobulin receptor (pIgR) that is essential for the secretion of polymeric antibody across mucosal surfaces. H. pylori SS1-infected wild-type and pIgR knockout (KO) mice were s led longitudinally for gastrointestinal bacterial load, antibody response, and histological changes. The gastric bacterial loads of wild-type and pIgR KO mice remained constant and comparable at up to 3 months postinfection (mpi) despite SS1-reactive secretory IgA in the intestinal contents of wild-type mice at that time. Conversely, abundant duodenal colonization of pIgR KO animals contrasted with the near-total eradication of H. pylori from the intestine of wild-type animals by 3 mpi. H. pylori was cultured only from the duodenum of those animals in which colonization in the distal gastric antrum was of sufficient density for immunohistological detection. By 6 mpi, the gastric load of H. pylori in wild-type mice was significantly lower than in pIgR KO animals. While there was no corresponding difference between the two mouse strains in gastric pathology results at 6 mpi, reductions in gastric bacterial load correlated with increased gastric inflammation together with an intestinal secretory antibody response in wild-type mice. Together, these results suggest that naturally produced secretory antibodies can modulate the progress of H. pylori infection, particularly in the duodenum.
Publisher: Wiley
Date: 28-09-2004
Publisher: Oxford University Press (OUP)
Date: 03-2006
Publisher: Elsevier BV
Date: 02-2004
Publisher: Wiley
Date: 05-03-2008
DOI: 10.1111/J.1523-5378.2008.00591.X
Abstract: A vaccine against Helicobacter pylori would be a desirable alternative to antibiotic therapy. Vaccination has been shown to be effective in animal models but the mechanism of protection is poorly understood. Previous studies investigating the gene expression in stomachs of vaccinated mice showed changes in adipokine expression correlated to a protective response. In this study, we investigate a well-characterized adipokine-leptin, and reveal an important role for leptin receptor signaling in vaccine-induced protection. Leptin receptor signaling-deficient (C57BL/Ks Lepr(db)), wild-type C57BL/Ks m littermates and C57BL/6 mice were vaccinated, and then challenged with H. pylori. Levels of bacterial colonization, antibody levels, and gastric infiltrates were compared. The local gene expression pattern in the stomach of leptin receptor signaling-deficient and wild-type mice was also compared using microarrays. Interestingly, while vaccinated wild-type lean C57BL/6 and C57BL/Ks m mice were able to significantly reduce colonization compared to controls, vaccinated obese C57BL/Ks Lepr(db) were not. All mice responded to vaccination, i.e. developed infiltrates predominantly of T lymphocytes in the gastric mucosa, and made H. pylori-specific antibodies. A comparison of expression profiles in protected C57BL/6 and nonprotected C57BL/Ks Lepr(db) mice revealed a subset of inflammation-related genes that were more strongly expressed in nonprotected mice. Our data suggest that functional leptin receptor signaling is required for mediating an effective protective response against H. pylori.
Publisher: American Society for Microbiology
Date: 03-2001
DOI: 10.1128/IAI.69.3.1714-1721.2001
Abstract: Protection in the murine model of Helicobacter pylori infection may be mediated by CD4 + T cells, but the mechanism remains unclear. To better understand how protection occurs in this model, we generated and characterized H. pylori urease-specific CD4 + T cells from BALB/c mice immunized with Salmonella enterica serovar Typhimurium expressing H. pylori urease (subunits A and B). The CD4 + T cells were found to be specific for subunit A (UreA). Upon antigen-specific stimulation, expression of interleukin 4 (IL-4), IL-10, gamma interferon (IFN-γ), and tumor necrosis factor alpha was induced. Immunocytochemical analysis showed that the majority of cells produced IFN-γ and IL-10. Adoptive transfer of the UreA-specific CD4 + T cells into naive syngeneic recipients led to a threefold reduction in the number of bacteria in the recipient group when compared to that in the nonrecipient group. Stomach colonization was also reduced significantly after transfer of these cells into patently infected mice. Adoptive transfer of UreA-specific CD4 + T cells into IL-4 receptor α chain-deficient BALB/c mice indicated that IL-4 and IL-13 were not critical in the control of bacterial load. In addition, synthetic peptides were used to identify three functional T-cell epitopes present in subunit A which were recognized by the UreA-specific T cells. Analysis of H. pylori -specific cellular immune responses in recipient challenged and nonrecipient infected mice indicated a strong local restriction of the response in infected animals. The implications of these findings for the mechanism of protection and the development of peptide-based vaccination are discussed.
Publisher: Elsevier BV
Date: 1997
Publisher: Frontiers Media SA
Date: 13-05-2022
DOI: 10.3389/FIMMU.2022.868225
Abstract: Helicobacter pylori is an important human pathogen that infects half the human population and can lead to significant clinical outcomes such as acute and chronic gastritis, duodenal ulcer, and gastric adenocarcinoma. To establish infection, H. pylori employs several mechanisms to overcome the innate and adaptive immune systems. H. pylori can modulate interleukin (IL) secretion and innate immune cell function by the action of several virulence factors such as VacA, CagA and the type IV secretion system. Additionally, H. pylori can modulate local dendritic cells (DC) negatively impacting the function of these cells, reducing the secretion of immune signaling molecules, and influencing the differentiation of CD4 + T helper cells causing a bias to Th1 type cells. Furthermore, the lipopolysaccharide (LPS) of H. pylori displays a high degree of phase variation and contains human blood group carbohydrate determinants such as the Lewis system antigens, which are proposed to be involved in molecular mimicry of the host. Lastly, the H. pylori group of outer membrane proteins such as BabA play an important role in attachment and interaction with host Lewis and other carbohydrate antigens. This review examines the various mechanisms that H. pylori utilises to evade the innate immune system as well as discussing how the structure of the H. pylori LPS plays a role in immune evasion.
Publisher: Springer International Publishing
Date: 2019
Abstract: Helicobacter pylori is a highly-adapted gastrointestinal pathogen of humans and the immunology of this chronic infection is extremely complex. Despite the availability of antibiotic therapy, the global incidence of H. pylori infection remains high, particularly in low to middle-income nations. Failure of therapy and the spread of antibiotic resistance among the bacteria are significant problems and provide impetus for the development of new therapies and vaccines to treat or prevent gastric ulcer, and gastric carcinoma. The expansion of knowledge on gastric conventional and regulatory T cell responses, and the role of T
Publisher: Oxford University Press (OUP)
Date: 30-08-2013
Publisher: Oxford University Press (OUP)
Date: 10-2009
Publisher: Public Library of Science (PLoS)
Date: 06-11-2015
Publisher: American Society for Microbiology
Date: 10-2010
DOI: 10.1128/IAI.00511-10
Abstract: Taenia ovis is a cestode parasite infecting primarily sheep as intermediate hosts and dogs as definitive hosts. The first highly effective, recombinant vaccine against a parasitic organism was developed against T. ovis infection in sheep. Three separate host-protective antigens (To16, To18, and To45W) have been cloned from the oncosphere of the parasite. We localize these antigens in the oncosphere by using quantitative immunogold labeling and transmission electron microscopy. The three antigens were uniquely associated with penetration gland cells. The cytoplasm and secretory granules of both penetration gland type 1 and type 2 cells exhibited statistically significant levels of staining for each of the three antigens. The intensity of labeling of the penetration gland type 1 cell was approximately three to five times greater ( P 0.01) compared to the level of staining intensity seen in the penetration gland type 2 cell. In activated oncospheres, secretory blebs were found to contain granules with a structure similar to those observed in the penetration gland cells. The granules within the secretory blebs were shown to stain specifically for the presence of each of the three host-protective antigens. The absence of surface location of the T. ovis antigens suggests that the parasite may not be susceptible to vaccine-induced antibody- and complement-mediated attack until some postoncospheral development has occurred after infection of the intermediate host.
Publisher: American Society of Tropical Medicine and Hygiene
Date: 04-2000
DOI: 10.4269/AJTMH.2000.62.466
Abstract: A vaccine trial was conducted with rhoptry-associated proteins 1 and 2 (RAP1 and RAP2) of Plasmodium falciparum in Saimiri boliviensis monkeys to compare the ability of parasite-derived (PfRAP1 and 2) and recombinant proteins (rRAP1 and 2) to induce protective immune responses and to find adjuvants suitable for use in humans. Eight groups of 6 monkeys each were immunized with parasite-derived or recombinant RAP1 and 2 with Freund's complete adjuvant (FCA) followed by Freund's incomplete adjuvant (FIA), Montanide ISA720 adjuvant, or CRL1005 adjuvant. Recombinant RAP1 and RAP2 were also administered separately, with Montanide ISA720. After 3 immunizations, monkeys were challenged by iv inoculation of 50,000 parasites of the Uganda Palo Alto strain of P. falciparum. Of the animals vaccinated using FCA/FIA, 1 of 6 control monkeys, 3 of 6 immunized with PfRAP1 and 2, and 2 of 6 with rRAP1 and 2 did not require drug treatment. Of the monkeys vaccinated with Montanide ISA720 adjuvant, 0 of the 6 control monkeys, 2 of 6 immunized with RAP1 and 2, 1 of 6 immunized with rRAP1, and 4 of 6 immunized with RAP2 did not require drug treatment. Two of 6 monkeys immunized with PfRAP1 and 2 with CRL1005 did not require treatment. All groups receiving RAP1, RAP2, or both had a significant decrease in initial parasite multiplication rates and there was a significant negative correlation between anti-RAP2 antibody and multiplication rates. Animals were rechallenged with the homologous parasite 126 days after the first challenge. Of the monkeys that did not require drug treatment after the first challenge, none developed detectable parasitemia following rechallenge.
Publisher: The American Association of Immunologists
Date: 03-2010
Abstract: Given the central role of intestinal dendritic cells (DCs) in the regulation of gut immune responses, it is not surprising that several bacterial pathogens have evolved strategies to prevent or bypass recognition by DCs. In this article, we will review recent findings on the interaction between intestinal DCs and prototypical bacterial pathogens, such as Salmonella, Yersinia, or Helicobacter. We will discuss the different approaches with which these pathogens seek to evade DC recognition and subsequent T cell activation. These erse strategies span to include mounting irrelevant immune responses, inhibition of Ag presentation by DCs, and stretch as far as to manipulate the Th1/Th2 balance of CD4+ T cells in the bacteria’s favor.
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2021
End Date: 2025
Funder: Australian Research Council
View Funded ActivityStart Date: 12-2016
End Date: 02-2022
Amount: $450,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2021
End Date: 06-2025
Amount: $989,000.00
Funder: Australian Research Council
View Funded Activity