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

在此输入文本，它是您的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(T1D)的有效发展是必不可少的。与胰岛素作为自身抗原的本质有关的一个重要的新兴概念是，CD4+T细胞对非传统的胰岛素多肽产生反应，包括来自胰岛素的氨基酸与来自另一种蛋白质(或胰岛素的另一区域)的氨基酸相连的杂交肽。在β细胞-细胞毒性CD8+T细胞的情况下，这是杀死β细胞必不可少的，对它们识别非传统胰岛素肽的能力知之甚少。类似于从癌症患者分离的肿瘤反应性CD8+T细胞识别的杂交肽，呈现在I类MHC分子上的杂交肽可以通过蛋白酶体催化的多肽剪接而产生。我们发现，在NOD小鼠中，H2-DB结合的杂交胰岛素肽是β细胞-细胞毒性T细胞的配体，这在I类MHC结合的杂交胰岛素肽与T1D之间建立了第一个联系。我们的项目将检验这一假设，即剪接的胰岛素多肽以及来自其他非规范来源的胰岛素多肽是T1D中β细胞-细胞毒CD8+T细胞的重要靶点。在目标1中，我们将利用质谱仪鉴定人类胰岛表达人类白细胞抗原-B*39：06或A*24：02的免疫表位，这两种基因都是T1D的易感基因，或T1D患者通常表达的A*02：01。关于原代人胰岛细胞上I类MHC分子呈递的多肽的信息有限。我们具有独特的优势来解决这一问题，这是基于我们用于鉴定MHC结合多肽(包括来自小样本)的可靠协议，以及允许识别剪接肽和来自其他非规范来源的那些多肽的工作流程。虽然我们的项目将专注于这些非传统的胰岛素多肽，但所有I类MHC结合的多肽都将被识别出来。在目标2中，我们将研究非常规胰岛素肽作为T1D中CD8+T细胞表位，并探讨它们在疾病发病机制中的重要性。我们最近开发的NOD小鼠模型结合人类白细胞抗原B*39：06、A*24：02或A*02：01转基因表达人胰岛素，将使我们能够检测AIM 1中鉴定的非常规人胰岛素多肽，以供胰岛渗透的CD8+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识别的T细胞特异性的致病性。T1D患者胰岛浸润的CD8+T细胞也将被检测。

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.