Diabetogenic Role of MHC Class I Alleles in NOD Mice

描述(申请人提供)：除了已知的特定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的CD8 T细胞反应在自身免疫性1型糖尿病(T1D)的发展中发挥重要作用。这一更新应用的总体目标仍然是在基于NOD的小鼠模型中剖析MHC I类限制导致糖尿病的CD8 T细胞发育的机制基础，并利用这些信息来确定潜在的临床可翻译的方法来减弱这种效应器。虽然编码KD和DB类I类分子的H2 g7 MHC单倍型对NOD小鼠T1D的发育是必不可少的，但它们也是许多非自身免疫倾向株的常见变体。这表明，H2g7 MHC I类分子通过与该菌株特有的许多其他疾病易感性(IDD)基因的相互作用，异常地介导了NOD小鼠的糖尿病致病CD8 T细胞反应。目的1将基于初步的mRNA转录谱和同源截断分析来验证这一假说，即位于先前已确定的Idd7基因座的NFkB抑制基因Nfkid的高表达变体是导致NOD小鼠的糖尿病原性CD8 T细胞无法进行胸腺负选择的重要原因。同样，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，可以异常地促进T1D的发展，也可能通过遗传背景的过程。事实上，我们发现，当在NOD基因组的背景下表达时，人类HLA-A2.1分子介导了导致糖尿病的CD8 T细胞反应。在这个NOD背景库中，HL A-A2.1限制性促糖尿病CD8 T细胞主要识别两种多肽，分别来自胰腺SS细胞蛋白胰岛素(INS)和胰岛特异性葡萄糖-6-磷酸酶催化亚单位相关蛋白(IGRP)。交联剂乙二亚胺(ECDI)可以有效地诱导免疫耐受，作为一种可能的多发性硬化症干预方法，这种方法正在进行临床试验。然而，基于细胞的治疗有许多障碍，可能的T1D干预方法只能考虑用于已经处于疾病发展的晚期前驱阶段的人类。因此，为了拓宽潜在的临床翻译，Aim 2将测试 新的初步数据支持，含有适当ECDI偶联INS和/或IGRP自身抗原肽的合成微粒治疗可以在NOD-HL A-A2小鼠中发挥晚期T1D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在人类中是一种潜在的高度有效的导致糖尿病的人类白细胞抗原I类变异体。因此，目标3将评估转基因表达的B39分子是否介导NOD小鼠的糖尿病致CD8 T细胞反应，如果是的话，识别这种I类变体所显示的？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.