Interluekin-23 (IL-23) is a pro-inflammatory cytokine critical to the regulation of innate and adaptive immune responses. The main role for this cytokine is in the proliferation and differentiation of the IL-17 producing CD4 T helper cell, Th17. Virus infection deregulates IL-23 expression and function, but little is known about the mechanism behind this phenomena. Here, I demonstrate a reduction of Toll like receptor (TLR) ligand-induced IL-23 expression in lymphocytic choriomeningitis virus (LCMV)-infected bone marrow-derived dendritic cells (BMDCs), indicating that a function of these cells is disrupted during virus infection. I propose a mechanism of TLR ligand-induced IL-23 expression inhibition upon LCMV infection via the deactivation of p38, AP-1, and NF-κB. Further analysis revealed a direct relationship between LCMV infection with the IL-10 and SOCS3 expression. To understand IL-23 function, I characterized IL-23-induced JAK/STAT signalling pathway and IL-23 receptor expression on human CD4 T cells. My results demonstrate that IL-23 induces activation of p-JAK2, p-Tyk2, p-STAT1, p-STAT3, and p-STAT4 in CD4 T cells. For the first time I show that IL-23 alone induces the expression of its own receptor components, IL-12Rβ1 and IL-23Rα, in CD4 T cells. Blocking JAK2, STAT1, and STAT3 activation with specific inhibitors detrimentally effected expression of IL-23 receptor demonstrating that activation of JAK/STAT signalling is important for IL-23 receptor expression. I also addressed the effect of viral infection on IL-23 function and receptor expression in CD4 T cells using cells isolated from HIV positive individuals. These studies were based on earlier reports that the expression of IL-23 and the IL-23 receptor are impaired during HIV infection. I demonstrate that the phosphorylation of JAK2, STAT1, and STAT3 induced by IL-23, as well as IL-23 receptor expression are deregulated in CD4 T cells isolated from HIV positive individuals. This study has furthered the understanding of how the expression and function of IL-23 is regulated during viral infections. / Thesis (Ph.D, Microbiology & Immunology) -- Queen's University, 2011-08-24 07:52:24.898

Les allergies aux produits chimiques et aux médicaments constituent un problème majeur de santé publique. L’objectif de ce travail est de mieux comprendre l’interaction entre les cellules dendritiques (DC) et les lymphocytes T (LT) dans les allergies induites par les haptènes métalliques (nickel et cobalt) et les médicaments [benzylpénicilline (BP)]. En présence des signaux de danger, les DC acquièrent un phénotype dit « mature » et présentent l’antigène apprêté aux LT spécifiques de cet antigène. Les LT représentent les cellules effectrices responsables d’une manière directe ou non des symptômes observés lors des réactions allergiques. Dans un premier temps, nous montrons que le nickel est capable d’induire un ratio d’interleukines (IL) IL-23/IL-12p70 élevé dans les DC favorisant ainsi la polarisation Th17 qui est détectée chez la majorité des patients allergiques au nickel. Nous montrons aussi pour la première fois une production de l’IL-27 par les DC activées par le nickel. Nous avons ensuite montré l’implication du TLR4 et de la voie Jak-STAT dans la régulation des cytokines membres de la famille de l’IL-12. L’activation de la voie Jak-STAT est nécessaire pour la réponse Th1 en favorisant la production de l’IL-12p70 et en inhibant la production de l’IL-23 par les DC activées par du nickel. Par ailleurs, nous avons identifié et, pour la première fois, une activation du facteur de transcription NFIL-3, au sein des DC, par le nickel et le cobalt voire d’une manière plus intense avec ce dernier. D’autre part, nous avons mis en évidence l’existence d’un répertoire de LT naïfs CD4+ et CD8+, provenant de la population générale, spécifiques du nickel. L’activation de ces LT requiert les molécules du complexe majeur d’histocompatibilité (CMH) et ils présentent un faible taux de réactivité croisée avec le cobalt. Simultanément, nous avons mis en évidence la possibilité de détecter des LT naïfs CD8+ spécifiques de la BP. L’activation de ces LT dépend des molécules du CMH de classe I et du protéasome. D’une manière générale, notre travail contribue à une meilleure compréhension des mécanismes des réactions allergiques d’une part, en montrant la fine régulation des cytokines membres de la famille de l’IL-12 dans les DC et d’autre part en élucidant les mécanismes de l’immunisation contre les molécules allergisantes. / Drug and chemical allergy is a major public health concern. The aim of this work is to understand the interaction between dendritic cells (DCs) and T-lymphocytes (LT) in allergic manifestations induced by metallic haptens (nickel and cobalt) and benzylpenicillin (BP). DCs capture the antigen, start maturation, migrate to the regional lymph node and activate hapten-specific T-cells. The latter will represent the effector cells responsible directly or not for the symptoms observed during allergic reactions. We showed that nickel induced a high ratio of interleukin (IL) IL-23 compared to IL-12p70 in DCs leading to Th17 polarization as seen in allergic patients. We also showed for the first time the production of IL-27 by nickel-activated DCs. Moreover, we showed the involvement of TLR4 and Jak-STAT pathways in IL-12 cytokine family regulation. The activation of the Jak-STAT pathway seems to maintain the IL-23/IL-12p70 balance by limiting IL-23 production and promoting Th1 polarization. Furthermore, we identified for the first time the activation of NFIL-3 in DC by nickel and cobalt, more intensely with the latter. In addition, nickel-recognizing CD4+ and CD8+ naïve T-cells repertoire was identified from the general population. These positive T-cells were shown to recognize nickel in the context of major histocompatibility complex (MHC) molecules. We also showed that a low frequency of nickel-recognizing CD4+ naïve T-cells cross-reacted with cobalt. Simultaneously, we showed the possibility of detecting a naïve CD8+ T-cells repertoire for BP. The activation of these specific T-cells requires MHC class I molecule and proteasome. In resume, our work contributes to a better understanding of allergic reactions, on one hand, by studying the fine regulation of the IL-12 cytokines family in DCs and on the other hand, by clarifying the mechanisms of immunization against drugs and chemicals.

Introdução: Diabetes tipo 1A(DM1A) é uma doença causada pela destruição autoimune das células beta. Em adição aos linfócitos T helper 1(Th1) e Th2, um subtipo específico de células T helper recentemente descrito, Th17, caracterizado pela produção da interleucina 17(IL-17A), IL-17F e IL-22, está também envolvido na imunidade adaptativa e autoimunidade, incluindo DM1A. A IL-23 tem função fundamental na expansão e sobrevivência das células Th17. A mesma é composta por 2 subunidades: a p19-específica (IL-23A) e a p40. Variantes dos genes IL-23A e de seu receptor (IL-23R) ou o aumento das concentrações séricas da IL-23 estão associados a várias doenças autoimunes, mas seus efeitos no DM1A não estão definidos. Com o intuito de avaliar a importância da IL-23 na patogênese do DM1A, as variantes dos genes IL23A e IL23R foram analisadas. Metodologia: A região codificadora e os regiões intrônicas proximais do gene IL23A, incluindo a região 5 proximal foram sequenciadas. Duas variantes do gene IL23A (rs2066808 e rs11171806) e duas do gene IL-23R (rs11209026 e rs10889677) foram também genotipadas. A amostra contou com 370 pacientes com DM1A e 314 indivíduos controles saudáveis. As medidas das concentrações séricas da IL-23 e os autoanticorpos pancreáticos e extra-pancreáticos foram determinados. Resultados: Nós observamos somente uma das seis variantes da IL-23 descritas nos bancos de dados (rs11171806 G>A localizada no exon 3) e descrevemos uma nova variante no gene IL-23A, que consistiu na substituição da citosina por timina na posição c.-403 (C>T) na região 5 proximal deste gene (encontrada em heterozigose em apenas uma paciente com DM1A, do sexo feminino, com 28 anos ao diagnóstico).Os alelos G dessas duas variantes estiveram em forte desequilíbrio de ligação (D\' = -0,825 para controles, p<2,0X10-6 e D\' = -0,902, p<2,0X10-17 para pacientes). Em consequência, a análise dos haplótipos destas variantes foi realizada. O haplótipo GG foi mais frequente nos controles (16.7%) do que nos pacientes com DM1A (9.5%), conferindo proteção à doença (pc = 0,0009, OR = 0,53) . A presença do haplótipo GG diferiu de acordo com a etnia no conjunto de pacientes e controles, sendo menor naqueles de etnia caucasóide (18%) em relação aos outros grupos (39%); p<0.0001. Entretanto, o efeito protetor da haplótipo GG foi independente da etnia. As duas variantes do gene IL23R (rs10889677 e rs11209026) tinham frequência alélica e genotípica semelhante entre pacientes com DM1A e controles. Não foi observada diferença significante nas concentrações da IL-23 entre 135 pacientes com DM1A (5,65 ± 14,0 pg/mL) e 112 indivíduos controles (9,06 ± 23,7pg/mL) (p =0,18). , mesmo quando analisamos apenas o pacientes com duração do diabetes inferior a dois anos, nos quais a resposta imune contra as células beta ainda está presente, (4.65 ± 6.94 pg/mL e 9.07 ± 23.62 pg/mL, p = 0.076). Não foi encontrada associação entre as variantes do gene IL23A com a idade diagnóstica, presença do peptídeo C residual e auto-anticorpo anti-descarboxilase do ácido glutâmico em pacientes com diagnóstico recente de DM1A. Estas variantes também não influenciaram na freqüência dos auto anticorpos extrapancreáticos: anti-tireoglobulina, anti-peroxidase, anti-21 hidroxilase, fator anti-núcleo, fator reumatóide e anti-citoplasma de neutrófilos. Conclusões: O haplótipo GG das variantes do gene lL23A (rs11171806 e rs2066808) foi associado a proteção ao DM1A. As variantes do gene IL23R (rs11209026 e rs10889677) não foram associadas ao DM1A. As concentrações séricas da IL-23 foram semelhantes entre os grupos. / Introduction: Type 1 diabetes mellitus (T1D) is a disorder caused by the immune-mediated destruction of insulin-secreting pancreatic beta cells. In addition to T helper 1 (Th1) and Th2 cells, a recently discovered subset of T helper cells, Th17, characterized by the production of interleukin 17 A (IL-17A), IL-17F, and IL-22 is also involved in adaptive immunity and autoimmunity, including T1D. The Interleukin IL-23 has a central role in the expansion and survival of Th 17 cells. It is composed of two subunits: p19-specific (IL-23A) and p40. Single nucleotide polymorphisms (SNPs) of IL-23A and IL-23 receptor (IL-23R) genes or increased IL-23 serum concentrations were associated with several autoimmune diseases, but their role in T1D has not been defined. We therefore searched for variants of IL-23A and IL-23R genes that could predispose to T1D. Methods:The coding regions and boundary intron sequences of IL-23A gene, including the 5 proximal region were sequenced. Two variants (rs2066808 and rs 11171806) of IL-23A and two of IL-23R (rs11209026 and rs10889677) genes were also genotyped. IL-23 serum levels and pancreatic and extra-pancreatic auto-antibodies were also determined. The cohort involved 370 patients with T1D and 314 healthy control subjects.Results: We observed only 1 out of 6 IL-23A coding variants (rs11171806 G>A localized in exon 3) described in a database repository . A new allelic variant of the IL-23A gene, consisting of the substitution of a cytosine by a thymine at position c.-403 (C>T) in the 5 proximal region of the IL-23A gene (found in heterozygosis in only 1 female patient with T1D) was described. The G alleles of rs11171806 and rs2066808 variants of IL-23A gene were in strong linkage disequilibrium (D\' = -0,825 for controls, p<2,0X10-6 and D\' = -0,902, p<2,0X10-17 for patients). So, further analyses were performed with the haplotypes instead of separated SNPs. The GG haplotype was more frequent in controls (16,7%) than in T1D patients (9,5%), conferring a protection to the disease (pc= 0,0009, OR = 0.53). The presence of haplotype GG was also different according to the ethnic group in the overall sample (patients+controls), when we pooled the Caucasians (18%) against the other groups (39%); p<0.0001. However, the lower susceptibility to T1D conferred by GG haplotype was independent of the ethnic group. Two IL-23R gene variants (rs10889677 and rs11209026) were also analyzed. The allelic and genotypic frequency of the variants did not differ between patients with T1D and control subjects. No significant differences were observed between the plasma IL-23 concentrations of 135 T1D patients (5.65 ± 14.0) and 112 control subjects (9.06 ± 23.7) (p = 0.18), even when we only the patients with less than 2 years disease duration (n = 43), when the immune attack to beta cells is still present, were included (4.65 ± 6.94 pg/mL and 9.07 ± 23.62 pg/mL, p = 0.076). No association was found between IL-23A variants with age at diagnosis of diabetes, presence of residual C-peptide levels or frequency of glutamic acid anti-decarboxilase antibody in patients with recent-onset T1D. Furthermore, these variants were not related to the presence of the extrapancreatic autoantibodies such as thyroid peroxidase (TPO) Ab, thyroglobulin (TG) Ab, 21-Hydroxilase (21OH) Ab, Anti nuclear factor (ANA) Ab, rheumatoid factor (FR) Ab and Neutrophil cytoplasmic (ANCA) Ab. Conclusions : The GG haplotype of lL23A gene variants( rs11171806 and rs2066808) was protective against T1D. The IL23R variants (rs11209026 and rs10889677) were not associated with susceptibility toT1D . IL-23 serum concentrations did not differ between T1D patients and controls.

Shiga toxin-producing E. coli (STEC) are globally relevant bacterial pathogens responsible for epidemic outbreaks of hemorrhagic diarrhea with variable progression to potentially fatal systemic Shiga toxicosis. Predictive clinical biomarkers and targeted therapeutic interventions for systemic Shiga toxicosis in diagnosed STEC patients are not available, and the impact of Shiga toxin production on STEC colonization and survival remain unclear. Improved murine models of STEC infection are needed to address knowledge gaps surrounding the gastrointestinal effects of Shiga toxins, as previously published models utilize ablation of host defense responses or microbiota depletion to facilitate colonization and are poorly suited for study of the effects of Shiga toxins on host responses. Dextran sulfate sodium (DSS) colitis in rodents has been associated with outgrowths of commensal E. coli in the literature, suggesting that DSS colitis could open a gastrointestinal niche usable by pathogenic STEC. This DSS colitis-based approach successfully induced susceptibility to robust colonization by two clinical isolate STEC strains in standard C57BL/6 mice. Studies using a Shiga-like toxin 2 (STX2)-producing clinical isolate STEC strain and its paired isogenic STX2 deletion strain (STEC(ΔSTX2)) revealed that STX2 was associated with delayed gastrointestinal clearance of STEC and concurrent reduction in colonic interleukin 23 (IL-23) axis transcripts known to be critical for pathogen clearance in other gastrointestinal pathogen models. In vivo reductions in IL-23 axis transcripts in the DSS+STEC model were supported by decreased IL-23 protein secretion by human macrophage-like cells during Shiga intoxication in vitro. Increased morbidity during STX2-producing STEC infection was associated with renal injury consistent with murine systemic Shiga toxicosis characterized by elevations in renal transcripts of molecular injury markers and histologically apparent renal tubular injury in a subset of mice. The dissertation research establishes a novel model of DSS colitis-facilitated murine STEC infection that recapitulates progression to systemic Shiga toxicosis in a subset of infected mice and demonstrates a clear STEC survival benefit associated with STX2 production. Shiga toxin-induced suppression of IL-23 axis signaling is a novel finding facilitated by the DSS+STEC model, demonstrating its utility for future delineation of the impacts of Shiga toxins on gastrointestinal host responses to STEC.

Thesis (Ph.D.)--University of Alabama at Birmingham, 2008. / Title from first page of PDF file (viewed on June 24, 2009). Includes bibliographical references (p. 88-101).

Introdução: Diabetes tipo 1A(DM1A) é uma doença causada pela destruição autoimune das células beta. Em adição aos linfócitos T helper 1(Th1) e Th2, um subtipo específico de células T helper recentemente descrito, Th17, caracterizado pela produção da interleucina 17(IL-17A), IL-17F e IL-22, está também envolvido na imunidade adaptativa e autoimunidade, incluindo DM1A. A IL-23 tem função fundamental na expansão e sobrevivência das células Th17. A mesma é composta por 2 subunidades: a p19-específica (IL-23A) e a p40. Variantes dos genes IL-23A e de seu receptor (IL-23R) ou o aumento das concentrações séricas da IL-23 estão associados a várias doenças autoimunes, mas seus efeitos no DM1A não estão definidos. Com o intuito de avaliar a importância da IL-23 na patogênese do DM1A, as variantes dos genes IL23A e IL23R foram analisadas. Metodologia: A região codificadora e os regiões intrônicas proximais do gene IL23A, incluindo a região 5 proximal foram sequenciadas. Duas variantes do gene IL23A (rs2066808 e rs11171806) e duas do gene IL-23R (rs11209026 e rs10889677) foram também genotipadas. A amostra contou com 370 pacientes com DM1A e 314 indivíduos controles saudáveis. As medidas das concentrações séricas da IL-23 e os autoanticorpos pancreáticos e extra-pancreáticos foram determinados. Resultados: Nós observamos somente uma das seis variantes da IL-23 descritas nos bancos de dados (rs11171806 G>A localizada no exon 3) e descrevemos uma nova variante no gene IL-23A, que consistiu na substituição da citosina por timina na posição c.-403 (C>T) na região 5 proximal deste gene (encontrada em heterozigose em apenas uma paciente com DM1A, do sexo feminino, com 28 anos ao diagnóstico).Os alelos G dessas duas variantes estiveram em forte desequilíbrio de ligação (D\' = -0,825 para controles, p<2,0X10-6 e D\' = -0,902, p<2,0X10-17 para pacientes). Em consequência, a análise dos haplótipos destas variantes foi realizada. O haplótipo GG foi mais frequente nos controles (16.7%) do que nos pacientes com DM1A (9.5%), conferindo proteção à doença (pc = 0,0009, OR = 0,53) . A presença do haplótipo GG diferiu de acordo com a etnia no conjunto de pacientes e controles, sendo menor naqueles de etnia caucasóide (18%) em relação aos outros grupos (39%); p<0.0001. Entretanto, o efeito protetor da haplótipo GG foi independente da etnia. As duas variantes do gene IL23R (rs10889677 e rs11209026) tinham frequência alélica e genotípica semelhante entre pacientes com DM1A e controles. Não foi observada diferença significante nas concentrações da IL-23 entre 135 pacientes com DM1A (5,65 ± 14,0 pg/mL) e 112 indivíduos controles (9,06 ± 23,7pg/mL) (p =0,18). , mesmo quando analisamos apenas o pacientes com duração do diabetes inferior a dois anos, nos quais a resposta imune contra as células beta ainda está presente, (4.65 ± 6.94 pg/mL e 9.07 ± 23.62 pg/mL, p = 0.076). Não foi encontrada associação entre as variantes do gene IL23A com a idade diagnóstica, presença do peptídeo C residual e auto-anticorpo anti-descarboxilase do ácido glutâmico em pacientes com diagnóstico recente de DM1A. Estas variantes também não influenciaram na freqüência dos auto anticorpos extrapancreáticos: anti-tireoglobulina, anti-peroxidase, anti-21 hidroxilase, fator anti-núcleo, fator reumatóide e anti-citoplasma de neutrófilos. Conclusões: O haplótipo GG das variantes do gene lL23A (rs11171806 e rs2066808) foi associado a proteção ao DM1A. As variantes do gene IL23R (rs11209026 e rs10889677) não foram associadas ao DM1A. As concentrações séricas da IL-23 foram semelhantes entre os grupos. / Introduction: Type 1 diabetes mellitus (T1D) is a disorder caused by the immune-mediated destruction of insulin-secreting pancreatic beta cells. In addition to T helper 1 (Th1) and Th2 cells, a recently discovered subset of T helper cells, Th17, characterized by the production of interleukin 17 A (IL-17A), IL-17F, and IL-22 is also involved in adaptive immunity and autoimmunity, including T1D. The Interleukin IL-23 has a central role in the expansion and survival of Th 17 cells. It is composed of two subunits: p19-specific (IL-23A) and p40. Single nucleotide polymorphisms (SNPs) of IL-23A and IL-23 receptor (IL-23R) genes or increased IL-23 serum concentrations were associated with several autoimmune diseases, but their role in T1D has not been defined. We therefore searched for variants of IL-23A and IL-23R genes that could predispose to T1D. Methods:The coding regions and boundary intron sequences of IL-23A gene, including the 5 proximal region were sequenced. Two variants (rs2066808 and rs 11171806) of IL-23A and two of IL-23R (rs11209026 and rs10889677) genes were also genotyped. IL-23 serum levels and pancreatic and extra-pancreatic auto-antibodies were also determined. The cohort involved 370 patients with T1D and 314 healthy control subjects.Results: We observed only 1 out of 6 IL-23A coding variants (rs11171806 G>A localized in exon 3) described in a database repository . A new allelic variant of the IL-23A gene, consisting of the substitution of a cytosine by a thymine at position c.-403 (C>T) in the 5 proximal region of the IL-23A gene (found in heterozygosis in only 1 female patient with T1D) was described. The G alleles of rs11171806 and rs2066808 variants of IL-23A gene were in strong linkage disequilibrium (D\' = -0,825 for controls, p<2,0X10-6 and D\' = -0,902, p<2,0X10-17 for patients). So, further analyses were performed with the haplotypes instead of separated SNPs. The GG haplotype was more frequent in controls (16,7%) than in T1D patients (9,5%), conferring a protection to the disease (pc= 0,0009, OR = 0.53). The presence of haplotype GG was also different according to the ethnic group in the overall sample (patients+controls), when we pooled the Caucasians (18%) against the other groups (39%); p<0.0001. However, the lower susceptibility to T1D conferred by GG haplotype was independent of the ethnic group. Two IL-23R gene variants (rs10889677 and rs11209026) were also analyzed. The allelic and genotypic frequency of the variants did not differ between patients with T1D and control subjects. No significant differences were observed between the plasma IL-23 concentrations of 135 T1D patients (5.65 ± 14.0) and 112 control subjects (9.06 ± 23.7) (p = 0.18), even when we only the patients with less than 2 years disease duration (n = 43), when the immune attack to beta cells is still present, were included (4.65 ± 6.94 pg/mL and 9.07 ± 23.62 pg/mL, p = 0.076). No association was found between IL-23A variants with age at diagnosis of diabetes, presence of residual C-peptide levels or frequency of glutamic acid anti-decarboxilase antibody in patients with recent-onset T1D. Furthermore, these variants were not related to the presence of the extrapancreatic autoantibodies such as thyroid peroxidase (TPO) Ab, thyroglobulin (TG) Ab, 21-Hydroxilase (21OH) Ab, Anti nuclear factor (ANA) Ab, rheumatoid factor (FR) Ab and Neutrophil cytoplasmic (ANCA) Ab. Conclusions : The GG haplotype of lL23A gene variants( rs11171806 and rs2066808) was protective against T1D. The IL23R variants (rs11209026 and rs10889677) were not associated with susceptibility toT1D . IL-23 serum concentrations did not differ between T1D patients and controls.

Introduction: Canadian First Nations experience a significantly higher rate of Mycobacterium tuberculosis (MTB) infection than non-Indigenous Canadians. Th17 cells are a subset of CD4+ T cells that are distinguished by their production of Interleukin-17A (IL-17A), an important cytokine for defense against mycobacteria. IL-17 is a primary contributor to the formation and stabilization of the lung granuloma, a biological containment vessel to protect the host from tuberculosis (TB). Past research with First Nations people has identified single nucleotide polymorphisms (SNPs) in the Th1 and Th2 immune pathways may affect their disease risk. However, SNPs in key Th17 related genes and the P2RX7 gene have not been explored in First Nations despite their important role against infectious diseases. Hypothesis: This research hypothesizes that distinct First Nations groups (Dene, Cree and Saulteaux) will have a different frequencies of SNPs in the key Th17 immunity related genes (IL-17A, IL-17AR, IL-23R, and IFN-γR) and the P2RX7 gene, as compared to a non-Indigenous Canadian group. Methods: SNP profiles (IL-17A rs2275913, IL-17RA rs4819554, IL-23R rs10889677, IFN-γR rs2234711 and P2RX7 rs3751143) were identified through literature research and the NCBI database was used for identifying gene motifs, primer locations and Restriction Enzyme cut sites. Polymerase Chain Reaction and Restriction Fragment Length Polymorphism analysis was performed on and visualized on agarose gel to determine specific allele frequencies. Four different Manitoba First Nations communities; the Northern Dene (Dene 1 N=69. Dene 2 N=52), Central Cree (N=46), and Southern Saulteaux (N=56), participated in this research and their SNP profiles were compared to a non-Indigenous Canadian cohort (N=99). Results: Allele frequencies for IL-17A were statistically different for every First Nation community when compared to the non-Indigenous cohort (Dene 1 p=0.0043, Dene 2 p=0.0000, Cree p=0.0001, Saulteaux p=0.0000). Allele frequencies for IL-17RA were statistically different for every First Nation community except Saulteaux when compared to the non-Indigenous cohort (Dene 1 p=0.0000, Dene 2 p=0.0028, Cree p=0.0000). Allele frequencies for IL-23R were statistically different for Dene 1 and Saulteaux community when compared to the non-Indigenous cohort (Dene 1 p=0.0002, Saulteaux p=0.0000). Allele frequencies for IFN-R were statistically different for Cree community when compared to the non-Indigenous cohort (Cree p=0.0026). Allele frequencies for P2RX7 were statistically different for both Dene communities when compared to the non-Indigenous cohort (Dene 1 p=0.0000, Dene 2 p=0.0000). Conclusions: An effective Th17 response is required to bring Th1 cells to infected tissues and to balance inflammatory responses. Functional SNPs may compromise an appropriate immune response and contribute to disease. This study demonstrate that the non-Indigenous population maintained a significantly different genetic profile when compared to the First Nations populations. / October 2016

Changes to the composition and function of the gut mononuclear phagocyte (MNP) compartment are associated with the development of intestinal inflammation. Much work has focused on the role of MNPs in gut-associated lymphoid tissue in maintaining homeostasis, however little is known regarding the roles of MNPs during colitis. We have investigated MNPs in the large intestinal lamina propria during the steady state and inflammation. One of our primary aims was to determine the contribution of MNP subsets to intestinal pathology. For our studies of inflammation, we focused mainly on the Helicobacter hepaticus infection &plus; anti-IL-10R model, which induces inflammation of the colon and caecum (typhlocolitis). We defined the composition of the MNP compartment alongside intestinal pathology scores throughout Hh &plus; anti-IL-10R typhlocolitis. Peak pathology, 2-3 weeks after induction of colitis, coincided with peak frequencies of CX₃CR1^int Ly6C^&plus; MNPs. Having observed the accumulation of CX₃CR1^int CD64^&plus; monocyte/macrophage MNPs in the inflamed lamina propria, we conducted comparative whole genome microarray analysis of these cells isolated from the large intestine three weeks after Hh &plus; anti-IL-10R treatment. CX₃CR1^int CD64^&plus; MNPs selectively expressed a variety of pro- and anti-inflammatory genes, including a number of genes which individually can both promote and negatively regulate inflammation. IL-23 is essential for Hh &plus; anti-IL-10R-induced intestinal pathology. We investigated the role of MNPs as a source of IL-23 which drives Hh &plus; anti-IL-10R colitis. Unexpectedly, our results indicate that normally hyporesponsive CX₃CR1^hi macrophages may act as the initial source of IL-23, which induces development of colitis. Recruitment of Ly6C^&plus; MHCII^&plus; MNPs to the lamina propria was IL-23-dependent, and these cells also expressed IL-23, which may establish a positive feedback loop of immune cell recruitment, activation and IL-23 production. Finally, we also examined how MNPs might be recruited to the colonic lamina propria during inflammation. Our studies support the conclusion that CCR6 is not required for accumulation of monocyte-derived populations in the inflamed intestine. We cannot rule out a role for CCR2, however preliminary data from the Hh &plus; anti-IL-10R colitis model suggest a potential role for CCR1 or its close relation CCRL2. Such pathways could represent new therapeutic targets in inflammatory bowel disease.

No description available.

No description available.