The "dark immunopeptidome" as a source of CD8 T cell epitopes in type 1 diabetes

在此输入文本，它是应用程序的新摘要信息。此部分不得超过30行文本。 T细胞对β细胞自身抗原胰岛素的反应对于1型糖尿病（T1 D）的有效发展至关重要。与胰岛素作为自身抗原的基本性质相关的一个重要的新兴概念是，CD 4 + T细胞应答发展为非常规胰岛素肽，包括杂交肽，其中来自胰岛素的氨基酸与来自另一种蛋白质（或胰岛素的另一个区域）的氨基酸连接。对于β细胞杀伤所必需的β细胞-细胞毒性CD 8 + T细胞，关于其识别非常规胰岛素肽的能力知之甚少。通过与从癌症患者分离的肿瘤反应性CD 8 + T细胞识别的杂合肽类似，可以通过蛋白酶体催化的肽剪接产生在I类MHC分子上呈递的杂合胰岛素肽。我们已经发现，H2-Db结合的杂合胰岛素肽是NOD小鼠中β细胞毒性T细胞的配体，在I类MHC结合的杂合胰岛素肽和T1 D之间建立了第一个联系。我们的项目将测试剪接的胰岛素肽和来自其他非经典来源的胰岛素肽是T1 D中β细胞毒性CD 8 + T细胞的重要靶点的假设。在目的1中，我们将使用质谱法来鉴定表达HLA-B*39：06或A*24：02的人胰岛的免疫肽组，这两种都是T1 D的易感因素，或A*02：01，通常由T1 D患者表达。有限的信息是可用的关于由I类MHC分子对原代人胰岛细胞的肽。基于我们用于表征MHC结合肽（包括小样本）的强大方案，以及允许识别剪接肽和来自其他非规范来源的肽的工作流程，我们处于独特的位置来解决这一问题。虽然我们的项目将集中在这些非传统的胰岛素肽，所有I类MHC结合肽将被确定。在目标2中，我们将研究非常规胰岛素肽作为T1 D中的CD 8 + T细胞表位，并探索其在疾病发病机制中的重要性。我们最近开发了转基因表达人胰岛素沿着HLA-B*39：06、A*24：02或A*02：01的NOD小鼠模型，这将使我们能够检查Aim 1中鉴定的非常规人胰岛素肽是否被胰岛浸润性CD 8 + T细胞识别。我们将使用这些模型和几种互补的方法来进一步评估我们确定的T细胞特异性的致病性。还将检查来自TlD患者的胰岛浸润性CD 8 + T细胞。

Enter the text here that is the new abstract information for your application. This section must be no longer than 30 lines of text. T cell responses to the beta cell autoantigen insulin are essential for efficient development of type 1 diabetes (T1D). An important emerging concept related to the essential nature of insulin as an autoantigen is that CD4+ T cell responses develop to unconventional insulin peptides, including hybrid peptides in which amino acids from insulin are linked to those from another protein (or another region of insulin). In the case of beta cell- cytotoxic CD8+ T cells, which are essential for beta cell killing, little is known about their ability to recognize unconventional insulin peptides. By analogy to hybrid peptides recognized by tumor-reactive CD8+ T cells isolated from cancer patients, hybrid insulin peptides presented on class I MHC molecules could be generated by proteasome-catalyzed peptide splicing. We have discovered that an H2-Db-bound hybrid insulin peptide is a ligand for beta cell-cytotoxic T cells in NOD mice, creating the first link between class I MHC-bound hybrid insulin peptides and T1D. Our project will test the hypothesis that spliced insulin peptides, and those derived from other non-canonical sources, are important targets of beta cell-cytotoxic CD8+ T cells in T1D. In Aim 1, we will use mass spectrometry to identify the immunopeptidome of human pancreatic islets expressing HLA-B*39:06 or A*24:02, both of which are predisposing for T1D, or A*02:01, commonly expressed by T1D patients. Limited information is available regarding the peptides presented by class I MHC molecules on primary human pancreatic islet cells. We are uniquely positioned to address this based on our robust protocols for the characterization of MHC-bound peptides, including from small samples, coupled with workflows that allow identification of spliced peptides and those derived from other non-canonical sources. Although our project will be focusing on such unconventional insulin peptides, all class I MHC-bound peptides will be identified. In Aim 2, we will investigate unconventional insulin peptides as CD8+ T cell epitopes in T1D and explore their importance in disease pathogenesis. Our recent development of NOD mouse models transgenically expressing human insulin along with HLA-B*39:06, A*24:02, or A*02:01 will allow us to examine the unconventional human insulin peptides identified in Aim 1 for recognition by islet-infiltrating CD8+ T cells. We will use these models and several complementary approaches to further assess the pathogenicity of the T cell specificities we identify. Islet- infiltrating CD8+ T cells from T1D patients will also be examined.