Diabetogenic Role of MHC Class I Alleles in NOD Mice

描述（由申请人提供）：除了长期以来已知的特定MHC II类分子的贡献外，越来越多的人认识到，在人类和NOD小鼠中，一些MHC I类变体也通过介导致病性CD 8 T细胞应答在自身免疫性1型糖尿病（T1 D）发展中发挥重要作用。该更新申请的总体目标仍然是在基于NOD的小鼠模型中剖析MHC I类限制性致糖尿病性CD 8 T细胞发育的机制基础，并使用该信息来鉴定减弱此类效应物的潜在临床可转化方法。虽然H2 g7 MHC单倍型编码的Kd和Db I类分子对NOD小鼠中的T1 D发展是必不可少的，但它们是也表征许多非自身免疫易感菌株的常见变体。这表明H2 g7 MHC I类分子通过与表征该菌株的许多其他疾病易感性（Idd）基因中的一些相互作用而异常地介导NOD小鼠中的致糖尿病性CD 8 T细胞应答。目的1将测试基于初步mRNA转录谱和同源截断分析的假设，即位于先前鉴定的Idd 7基因座内的NFkB抑制性Nfkbid基因的高表达变体是导致致糖尿病CD 8 T细胞在NOD小鼠中经历胸腺阴性选择失败的重要因素。类似地，流行病学研究表明，在人类中，某些常见的I类分子如HLA-A2.1也可能通过遗传背景过程异常地促成T1 D的发展。事实上，我们发现当在NOD基因组的背景下表达时，人HLA-A2.1分子介导致糖尿病的CD 8 T细胞应答。该NOD背景储备中的HLA-A2.1限制性致糖尿病性CD 8 T细胞主要识别两种肽，每种肽均来源于胰腺β细胞蛋白胰岛素（INS）和胰岛特异性葡萄糖-6-磷酸酶催化亚基相关蛋白（IGRP）。通过交联剂乙烯碳二亚胺（ECDI）可以有效地诱导免疫耐受性结合自体白细胞的抗原，这种方法是在临床试验中作为一种可能的多发性硬化症干预。然而，基于细胞的疗法存在许多障碍，并且可能的T1 D干预方法只能在已经处于疾病发展的后期前驱阶段的人类中考虑。因此，为了拓宽潜在的临床翻译，Aim 2将测试 由新的初步数据支持的可能性，即用携带适当的ECDI偶联的INS和/或IGRP自身抗原肽的合成微粒治疗可以在NOD-HLA-A2小鼠中发挥晚期疾病阶段T1 D保护作用，和/或能够通过胰岛移植逆转已建立的疾病。最后，流行病学证据表明B39是人类中潜在的高度有效的致糖尿病性HLA I类变体。因此，目标3将评估转基因表达的B39分子是否介导NOD小鼠中的致糖尿病性CD 8 T细胞应答，如果是，则鉴定由这种I类变体展示的CD 8细胞自身抗原，并测试它们作为扩大的疾病干预试剂的能力。

DESCRIPTION (provided by applicant): In addition to long known contributions from particular MHC class II molecules, there is growing appreciation that in both humans and NOD mice some MHC class I variants also play an essential role in autoimmune type 1 diabetes (T1D) development by mediating pathogenic CD8 T-cell responses. The overall goal of this renewal application continues to be dissection in NOD based mouse models of the mechanistic basis for MHC class I restricted diabetogenic CD8 T-cell development, and use of this information to identify potentially clinically translatable means to attenuate such effectors. While the H2g7 MHC haplotype encoded Kd and Db class I molecules are essential to T1D development in NOD mice, they are common variants also characterizing many non-autoimmune prone strains. This suggested H2g7 MHC class I molecules aberrantly mediate diabetogenic CD8 T-cell responses in NOD mice through interactions with some of the many other disease susceptibility (Idd) genes characterizing this strain. Aim 1 will test the hypothesis based on preliminary mRNA transcript profiling and congenic truncation analyses that a hyper-expression variant of the NFkB inhibitory Nfkbid gene located within the previously identified Idd7 locus is an important contributor to the failure of diabetogenic CD8 T-cells to undergo thymic negative selection in NOD mice. Similarly, epidemiological studies indicate that in humans certain common class I molecules such as HLA-A2.1 can aberrantly contribute to T1D development also likely through a genetically contextual process. Indeed, we found that when expressed in the context of the NOD genome, human HLA-A2.1 molecules mediate diabetogenic CD8 T-cell responses. HLA-A2.1 restricted diabetogenic CD8 T-cells in this NOD background stock primarily recognize two peptides each derived from the pancreatic ss cell proteins insulin (INS) and islet specific glucose-6-phosphatase catalytic subunit related protein (IGRP). Immunological tolerance can be efficiently induced to antigens bound to autologous leukocytes by the cross-linking agent ethylene carbodiimide (ECDI), and such an approach is in a clinical trial as a possible multiple sclerosis intervention. However, there are many hurdles to cell based therapies, and possible T1D intervention approaches can only be considered in humans already at a late prodromal stage of disease development. Therefore, to broaden potential clinical translation, Aim 2 will test the possibility supported by new preliminary data that treatment with synthetic microparticles bearing appropriate ECDI coupled INS and/or IGRP autoantigenic peptides can exert late disease stage T1D protective effects in NOD-HLA-A2 mice, and/or enables reversal of established disease by pancreatic islet transplantation. Finally, epidemiological evidence implicates B39 as a potentially highly potent diabetogenic HLA class I variant in humans. Thus, Aim 3 will assess whether transgenically expressed B39 molecules mediate diabetogenic CD8 T-cell responses in NOD mice, and if so, identify ß cell autoantigens displayed by this class I variant, and test their capacity to serve as broadened disease intervention reagents.