The role of IL-27 in iv tolerance in EAE

描述（由申请方提供）：静脉注射（i. v.）注射可溶性抗原可以在实验性自身免疫性脑脊髓炎（EAE）（多发性硬化的动物模型）中诱导抗原特异性耐受，并有效地抑制疾病。静脉注射的自身抗原诱导致耐受性树突状细胞（DC），其产生IL-27，一种有效的免疫调节细胞因子。虽然在野生型EAE小鼠中可以成功诱导耐受性，但缺乏IL-27受体的小鼠具有抗性，这表明IL-27在耐受性诱导中起关键作用。 这一建议的中心假设是，在EAE中静脉内给予自身抗原导致DC产生IL-27，这反过来又诱导致耐受性DC和调节性Tr 1细胞，导致耐受。 为了验证这一假设，提出了三个具体的目标：目的1）研究IL-27在产生致耐受性DC和抗原特异性1型调节性T（Tr 1）细胞中的作用。我们假设IL-27通过旁分泌（抑制髓鞘特异性Th 1/Th 17细胞和诱导Tr 1细胞）和自分泌（诱导和扩增致耐受性DC）机制在静脉注射耐受中起关键作用。目的2）探讨Galectin-1/IL-27信号通路在静脉注射耐受诱导中的作用。半乳糖凝集素-1是一种内源性聚糖结合蛋白，由TGFAP产生，可赋予DC IL-27依赖性致耐受性潜力。我们已经发现MOG反应性Tcl 4刺激DC产生IL-27，这是一种主要依赖于半乳糖凝集素-1的作用。IL-27，反过来，可以刺激 DC表达高水平的半乳糖凝集素-1。此外，半乳糖凝集素-1缺陷型小鼠对EAE中静脉内耐受性的诱导具有抗性。在这个目标中，我们将测试我们的假设，即静脉注射autoAg将触发Ag特异性nT细胞优先与DC形成聚集体，产生半乳糖凝集素-1，并在体内诱导致耐受性DC。目的3）检测外源性IL-27对EAE静脉注射耐受诱导的影响。鉴于IL- 27在耐受诱导中的重要作用，我们假设rmIL-27的施用将促进静脉内注射自身抗原后致耐受性/调节性DC和T细胞的发育。因此，施用外源性IL-27可以增强静脉内耐受的治疗效果，并减少最大效果所需的自身抗原的剂量。这将降低对耐受性自身抗原产生自身抗体或不良免疫应答的可能性。 目的1和2研究静脉注射耐受诱导的基本机制，而目的3侧重于将我们的发现转化为治疗。从这些研究中获得的信息将导致更好地理解静脉注射耐受的机制，并为CNS炎性脱髓鞘的新型免疫治疗提供基础。

DESCRIPTION (provided by applicant): Intravenous (i.v.) injection of soluble antigens can induce antigen-specific tolerance in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, and effectively suppresses the disease. I.V. injected autoantigen induces tolerogenic dendritic cells (DCs), which produce IL-27, a potent immunoregulatory cytokine. While tolerance can be successfully induced in wild-type EAE mice, mice lacking IL-27 receptor are resistant, demonstrating that IL-27 plays a crucial role in tolerance induction. The central hypothesis of this proposal is that i.v. administration of autoantigen in EAE causes DCs to produce IL-27, which in turn induces tolerogenic DCs and regulatory Tr1 cells, leading to tolerance. To test this hypothesis, three specific aims are proposed: Aim 1) To study the role of IL-27 in generation of tolerogenic DCs and antigen-specific type 1 regulatory T (Tr1) cells in i.v. tolerance. We hypothesize that IL-27 plays a key role in i.v. tolerance by both paracrine (suppression of myelin-specific Th1/Th17 cells and induction of Tr1 cells) and autocrine (induction and expansion of tolerogenic DCs) mechanisms. Aim 2) To investigate the role of the galectin-1/IL-27 pathway in i.v. tolerance induction. Galectin-1 is an endogenous glycan-binding protein, produced by Tregs that can endow DCs with IL-27-dependent tolerogenic potential. We have found that MOG-reactive Tregs stimulate DCs to produce IL-27, an effect that is largely galectin-1-dependent. IL-27, in turn, can stimulate DCs to express a high level of galectin-1. Further, galectin-1 deficient mice are resistant to the induction of i.v. tolerance in EAE. In this aim we will test our hypothesis that i.v. injection of autoAg will trigger Ag-specific nTregs to preferentially form aggregates with DCs, produce galectin-1, and induce tolerogenic DCs in vivo. Aim 3) To test the effect of exogenous IL-27 on i.v. tolerance induction in EAE. Given the important role of IL- 27 in tolerance induction, we hypothesize that administration of rmIL-27 will promote development of tolerogenic/regulatory DCs and T cells upon i.v. injection of autoantigen. Hence, administration of exogenous IL-27 can enhance the therapeutic effect of i.v. tolerance, and reduce the dose of autoantigen required for maximal effect. This will decrease the likelihood of developing autoantibodies or adverse immune responses to the tolerizing autoantigen. Aims 1 and 2 study basic mechanisms of i.v. tolerance induction, while Aim 3 focuses on translation of our findings into therapy. The information gained from these studies should lead to a better understanding of the mechanisms of i.v. tolerance and provide the basis for novel immunotherapies for CNS inflammatory demyelination.