Role of Novel T Cell Costimulatory Pathways in Allograft Rejection and Tolerance

T细胞免疫球蛋白粘蛋白（TIM）家族是一种新型的受体-配体对，在T细胞免疫中起着重要的作用。 激活、分化和效应子/记忆功能，以及在自体免疫系统中调节免疫应答。 免疫和过敏/哮喘。TIM-1由活化的Th 1和Th 2细胞表达，并且其表达是 优先在终末分化的Th 2细胞中维持。TIM-1的配体是TIM-4， 主要在APC上表达。最近的研究表明，TIM-1可能差异调节T辅助细胞， (Th1/Th 2）分化，以及自身免疫性脑脊髓炎。目前，人们所知甚少 TIM-1：TIM-4通路在同种免疫反应和自身免疫性糖尿病中的作用。初步 我们小组的研究表明TIM-1：TIM-4途径在同种免疫中起重要作用， 特别是同种异体反应性T辅助细胞分化和可能的调节性T细胞产生/功能。 此外，已经确定，一方面自身反应性Th 1细胞和调节性T细胞的平衡， 细胞和Th 2细胞在决定NOD小鼠中自身免疫性糖尿病的结果方面是至关重要的。 我们的中心假设是，TIM-1：TIM-4通路通过调节Th 1/Th 2细胞分化， 可能调节T细胞的产生和功能，在同种免疫和自身免疫中起重要作用。 反应和宽容。本提案的主要目标是界定 TIM-1：TIM-4通路在体内调节免疫应答中作为开发新策略的手段， 实现持久和可再现的耐受性，并防止复发性自身免疫的发展， 同种异体胰岛移植物在这方面，我们的方法是测试和探索新的理性的机制， 靶向多种途径的联合策略导致同种异体反应性和自身反应性T细胞的沉默， 细胞，并在胰岛同种异体移植的NOD受体中向细胞和/或细胞因子调节倾斜平衡， 移植物在具体目标1中，我们将研究靶向TIM-1：TIM-4通路对同种免疫的影响。 和胰岛同种异体移植排斥模型中的体内自身免疫应答。在具体目标2中，我们将剖析 TIM-1：TIM-4通路在同种异体免疫、自身免疫和耐受中的作用机制，重点是T细胞 扩增、分化和凋亡。这些研究将利用CD 4+和CD 8 + TCR转基因动物 具有确定的同种异体（B6背景）和自体（NOD背景）特异性。MHC四聚体也将是 用于研究靶向TIM-1对NOD小鼠中自身反应性CD 4+和CD 8 + T细胞的作用机制。 最后，在具体目标3中，我们将特别关注TIM-1：TIM-4途径在产生 和/或体内调节性T细胞的功能。使用foxp 3-GFP敲入报告基因小鼠对B6和NOD 背景下，我们将测试的假设，基于最初的初步数据，即TIM-1：TIM-4途径可能 在体内CD 4 + CD 25+调节性T细胞的产生和/或功能中具有重要作用。 总的来说，我们的研究应该提供有用的新数据，这些数据可能会导致新策略的发展， 诱导对胰岛同种异体移植物的耐受性以转化至灵长类动物和人类。

The T cell immunoglobulin mucin (TIM) family of novel receptor-ligand pairs plays important roles in T cell activation, differentiation and effector/memory function, and in regulation of immune responses in auto- immunity and allergy/asthma. TIM-1 is expressed by activated Th1 and Th2 cells and its expression is sustained preferentially in terminally differentiated Th2 cells. The ligand for TIM-1 is TIM-4, which is predominantly expressed on APCs. Recent studies indicate that TIM-1 may differentially regulate T helper cell (Th1/Th2) differentiation in asthma/allergy, and autoimmune encephalomyelitis. At present, little is known about the role of the TIM-1 :TIM-4 pathway in alloimmune responses and autoimmune diabetes. Preliminary studies from our group indicate that the TIM-1:TIM-4 pathway plays an important role in alloimmunity, particularly alloreactive T helper cell differentiation and possibly regulatory T cell generation/function. Furthermore, it is well established that the balance of autoreactive Th1 cells on one hand and regulatory T cells and Th2 cells on the other is critical in determining the outcome of autoimmune diabetes in NOD mice. Our central hypothesis is that the TIM-1:TIM-4 pathway, by modulating Th1/Th2 cell differentiation and possibly regulatory T cell generation and function, plays an important role in alloimmune and autoimmune responses, and tolerance. The main goal of this proposal is to define the functions and mechanisms of the TIM-1:TIM-4 pathway in regulating immune responses in vivo as a means of developing novel strategies to achieve durable and reproducible tolerance, and preventing the development of recurrent autoimmunity to islet allografts. In that regard, our approach is to test and explore the mechanisms of novel rational combination strategies that target multiple pathways resulting in silencing of alloreactive and autoreactive T cells, and tipping the balance towards regulation by cells and/or cytokines in NOD recipients of islet allo- grafts. In Specific Aim 1 we will investigate the effects of targeting the TIM-1 :TIM-4 pathway on alloimmune and autoimmune responses in vivo in models of islet allograft rejection. In Specific Aim 2 we will dissect the mechanisms of action of TIM-1:TIM-4 pathway in alloimmunity, autoimmunity and tolerance, focusing on T cell expansion, differentiation, and apoptosis. These studies will utilize CD4+ and CD8+ TCR transgenic animals with defined allo- (B6 background) and auto- (NOD background) specificities. MHC tetramers will also be used to study the mechanisms of targeting TIM-1 on autoreactive CD4+ and CD8+ T cells in NOD mice. Finally, in Specific Aim 3 we will focus specifically on the role of TIM-1:TIM-4 pathway in the generation and/or function of regulatory T cells in vivo. Using foxp3-GFP knock-in reporter mice on B6 and NOD backgrounds, we will test the hypothesis, based on initial preliminary data, that the TIM-1:TIM-4 pathwaymay have an important role in the generation and/or function of CD4+CD25+ regulatory T cells in vivo. Overall, our studies shouldyield useful new data that maylead to development of novel strategies to induce tolerance to islet alloarafts to translate to orimates and humans.