Multiple Sclerosis (MS) is a neurodegenerative autoimmune disease that affects millions of people worldwide. Although the exact cause of MS is unknown, it is clear that CD4+ T helper cells play a significant role, namely T helper 1 (Th1) and T helper 17 (Th17) cells. The Notch family of proteins plays a role in the development and differentiation of T helper cells. Previous data has shown that inhibition of Notch impairs the ability of T helper cell differentiation. Additionally specific inhibition of certain Notch members inhibits specific T helper cell differentiation, for example the inhibition of Notch 1 inhibits Th1 and iTreg polarization [Samon et al., 2008]. However, the effects of the other Notch family members on CD4+ T cells are not fully studied. We propose that Notch 3 plays an extensive role in the regulation of Th1, Th2, Th17, and iTreg polarizations. In addition, we propose that Notch 3 regulates function of T helper cell function in the mouse model of MS, experimental autoimmune encephalomyelitis (EAE). Data in this thesis show that Notch 3 plays a significant role in the polarization of Th1, Th17 and iTreg polarization [Karlsson et al., 2011]. We present evidence that the heterozygous and homozygous Notch 3 knockout exhibits a significant decrease in polarization toward Th1, Th17 and iTreg cell fates. Exopolysaccharide (EPS) is a compound that has been previously shown to play a protective role in other inflammatory diseases. EPS has been shown to produce anti-inflammatory macrophages. We propose that a similar anti-inflammatory effect might be possible in EAE. We found that EPS had a significant effect on EAE induction, decreasing the onset and peak disease score. EPS also reduced the concentration of IFN-γ, IL17A, and GM-CSF in the supernatants of the splenocytes after restimulation with MOG. Further experimental data is needed to prove the effects of EPS on EAE and the method by which EPS function. These data indicate that Notch 3 could be crucial in regards to EAE due to the effects on Th1 and Th17 which are instrumental in EAE induction [Raphael et al., 2015].

No description available.

京都大学 / 新制・論文博士 / 博士(医学) / 乙第13536号 / 論医博第2276号 / 新制||医||1065(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 河本 宏, 教授 妹尾 浩, 教授 中川 一路 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

No description available.

No description available.

Studies examining the immune response upon exposure to chitin microparticles in living models have reached drastically differing conclusions, and the reason remains unclear. One notable issue between the experiments is that they have not characterized their chitin preparations for degree of acetylation. They all use different chitin processing methods prior to administration, which could potentially be the source of the variance between studies. Chitin and chitosan preparations specified in the literature and several novel preparations were analyzed for degree acetylation (DA) using High Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD). It was found that autoclaving and sonication processing steps do not have a significant influence on degree of acetylation. Chitin and chitosan preparations were used to create a dose-response curve of DA compared to cytokine elicitation from THP-1 monocytes, and it was found that the initial response was dominated by TNF (similar to previous studies), though after 12 hours showed a tip toward the start of an IL-1β-dominated Th17 effector response. This study also confirmed that immunostimulatory effects can occur from chitin and chitosan particles at orparticles, which would have long residence times in air, might be implicated in initiating allergic or asthmatic processes.

No description available.

No description available.

Aging is accompanied by dysregulated immune function resulting in increased susceptibility of the elderly to diseases caused by microbial pathogens. There exists a multitude of data suggesting decreased resistance of the elderly to a variety of intracellular pathogens but there is no data relating the effect of aging on the immune response against Brucella. To elucidate the mechanism of immune dysregulation in old, old and young DBA/2 and BALB/c mice were infected with wild-type B. abortus strain 2308. The old and young mice were also vaccinated with vaccine B. abortus strain RB51 over-expressing Cu-Zn superoxide dismutase (SOD) and then challenged with B. abortus strain 2308 to determine the effect of vaccination in old vs. young mice. Specific IgG1 and IgG2a response to Brucella antigens were also evaluated to determine the effect of aging on Th-specificity of the immune response against Brucella infection. The immune response in aged vs. young mice was further assessed using RT-PCR and cytokine antibody array to determine the type of T-helper response. The experimental results indicate that all mice, regardless of age, survived infection ranging from doses of 2 x 104 to - 2 x 108 CFU. Though the older DBA/2 mice had a higher organism burden after 1 week of infection, these mice cleared Brucella infection more efficiently (5 weeks post-infection) than young mice. Vaccination with strain RB51 over-expressing SOD provided significant protection in young DBA/2, young BALB/c and old BALB/c mice but not in old DBA/2 mice after strain 2308 challenge. The results also suggest that old mice produced a different magnitude of IgG1 and IgG2a response to bacterioferritin and SOD of Brucella. The data suggests that both Th17 as well as Th1 responses were accentuated in old mice as compared to young mice following infection with Brucella. How the Th17 and Th1 branches of immune system work together enabling old mice to clear Brucella better than young mice warrants future investigation. / Master of Science

Les lymphocytes Th17 forment une population de cellules T CD4+ pro-inflammatoires, impliqués non seulement dans l'élimination d'agents pathogènes, mais ayant aussi un rôle délétère dans l'induction de maladies inflammatoires chroniques. Ils expriment spécifiquement le récepteur de chimiokines CCR6, qui a pour ligand le CCL20 mais aussi les β-defensine-1, 2 et 3, peptides ayant une activité antimicrobienne. Les cellules souches mésenchymateuses (CSMs) représentent une population cellulaire hétérogène exerçant diverses propriétés immunomodulatrices.Les résultats obtenus dans ce travail de thèse montrent que l'environnement inflammatoire contribue à augmenter l'adhésion des lymphocytes Th17 aux CSMs, et qu'elle est régulée par l'interaction du CCR6 avec ses ligands ; que les CSMs exercent, en partie via la sécrétion de PGE2, des effets anti-inflammatoires en faisant acquérir un phénotype régulateur aux lymphocytes Th17 différenciés, soulignant ainsi la plasticité de ces derniers.De plus, nous avons montré que les lymphocytes Th17 activés par l'antigène produisent du CCL20 et induisent, via la production de l'IL-17 et de l'IL-22, la sécrétion d'hBD-2, mais pas celle des hBD-1 et 3, par des kératinocytes épidermiques humains et de la peau reconstituée; que le CCL20, ainsi que la hBD-2, induisent l'arrêt de ces cellules sur l'endothélium enflammé in vitro en conditions de cisaillement. Finalement, l'activation spécifique d'antigène des lymphocytes Th17 entraîne une perte de l'expression de CCR6, ce qui provoque ainsi un état transitoire de non réponse à une nouvelle stimulation de ces cellules avec les ligands de CCR6, permettant leur migration ultérieure hors du tissu enflammé. / Th17 cells form a population CD4+ T cells with strong pro-inflammatory properties that are not only involved in the clearance of pathogens, but also play a deleterious role of in the pathogenesis of inflammatory disease. Th17 cells specifically express CCR6, a chemokine receptor that binds to its unique chemokine ligand, CCL20, as well as to human β-defensin (hBD)-1, 2 and 3, peptides with anti-microbial activity. Mesenchymal stem cells (MSC) represent a heterogenous population that exert broad immunomodulatory effects.The results from the studies carried out during this thesis show that the inflammatory environment contributes to increased adhesion of Th17 cells to MSCs, which is mediated via the interaction of CCR6 with its ligands, and that MSCs exert, in part via the secretion of PGE2, anti-inflammatory effects through the induction of a T regulatory cell phenotype in fully differentiated tissue-infiltrating Th17 cells, thereby underscoring the plasticity of the latter cells.Furthermore, the results show that antigen-activated Th17 cells produce CCL20 and induce, via the production of both IL-17 and IL-22, the secretion of hBD-2, but not 1 and 3, by normal human epidermal keratinocytes and reconstituted skin, and that CCL20, as well as hBD-2, induce arrest of these cells onto inflamed endothelium in vitro under conditions of shear stress. Finally, antigen-specific activation of Th17 cells also causes a loss of CCR6 expression from their cell surface and thus results in a transitory state of non-responsiveness to further stimulation of these cells with CCR6 ligands, which is likely to permit their subsequent migration out of inflamed tissue.