Antigens Recognized by CD8+ T Cells in Type 1 Diabetes

描述（由申请人提供）：1型糖尿病（T1D）是一种以T细胞介导的胰岛细胞破坏为特征的自身免疫性疾病。对非肥胖糖尿病（NOD）小鼠模型的研究表明，CD8+ T细胞是T1D发展所必需的。我们使用从NOD小鼠中分离的细胞毒性CD8+ T细胞克隆来鉴定早期胰岛素T细胞的两个抗原靶点。这些是胰岛特异性葡萄糖-6-磷酸酶催化亚基相关蛋白（IGRP）和营养不良肌强直激酶（DMK）。与已知的第三个早期胰岛素CD8+ T细胞靶标（即胰岛素）一起考虑，这三个特异性可以共同解释NOD小鼠中多达一半的胰岛浸润CD8+ T细胞。在这里，我们将利用来自hla转基因NOD小鼠的胰岛浸润T细胞来绘制HLA-A*0201限制性T细胞靶向的这些细胞抗原的表位，从而将我们的发现转化为人类T1D。假设HLA-A*0201阳性患者和hla转基因小鼠将在他们识别的表位方面表现出重叠的特异性，然后将进行评估。接下来，我们新开发的通过内吞受体DEC-205将细胞抗原传递到稳态树突状细胞（dc）的能力将允许我们测试这种治疗将导致CD8+ T细胞耐受性和疾病改善的假设。我们将研究DC靶向igrp衍生肽对转移和内源性igrp反应性CD8+ T细胞的影响，利用使我们能够在数量和功能方面监测igrp特异性T细胞的方法，包括我们设计的允许检测igrp特异性T细胞体内细胞毒性的细胞毒性测定。这些研究之所以选择IGRP，是因为它是NOD小鼠中一种重要的CD8+ T细胞抗原。最后，一种“高通量”的抗原发现方法将被用于在NOD小鼠模型中更完整地表征CD8+ T细胞靶向的抗原，这将增加其在优化治疗和探索T1D免疫发病机制方面的效用。骨髓干细胞逆转录病毒转导将用于从特异性未知的早期胰岛素细胞毒性CD8+ T细胞克隆中快速产生表达T细胞受体的NOD小鼠。这些小鼠将被用作发现抗原的T细胞来源。总之，我们的工作将有助于开发干扰致病性T细胞群的策略，以及监测自身免疫活性的检测方法。

DESCRIPTION (provided by applicant): Type 1 diabetes (T1D) is an autoimmune disease characterized by T cell-mediated destruction of the pancreatic islet ( cells. Studies of the nonobese diabetic (NOD) mouse model of the disease indicate that CD8+ T cells are required for T1D development. We used ( cell-cytotoxic CD8+ T cell clones isolated from NOD mice to identify two antigenic targets for early insulitic T cells. These are islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) and dystrophia myotonica kinase (DMK). Considered together with the third known target of early insulitic CD8+ T cells (i.e., insulin), these three specificities can collectively account for up to half of the islet-infiltrating CD8+ T cells in NOD mice. Here we will translate our findings to human T1D by using islet-infiltrating T cells from HLA-transgenic NOD mice to map the epitopes of these ( cell antigens that are targeted by HLA-A*0201-restricted T cells. The hypothesis that HLA-A*0201 -positive patients and HLA-transgenic mice will exhibit overlapping specificities with respect to the epitopes they recognize will then be evaluated. Next, our newly developed ability to deliver ( cell antigens to steady-state dendritic cells (DCs) via the endocytic receptor DEC-205 will permit us to test the hypothesis that this treatment will result in CD8+ T cell tolerance and improvement of disease. We will examine the impact of DC targeting of an IGRP-derived peptide on both transferred and endogenous IGRP-reactive CD8+ T cells, utilizing approaches that will enable us to monitor IGRP-specific T cells in terms of both number and function, including a cytotoxicity assay that we have devised to permit detection of IGRP-specific T cell cytotoxicity in vivo. IGRP has been chosen for these studies, because it is a CD8+ T cell antigen of major importance in NOD mice. Finally, a "high-throughput" approach to antigen discovery will be employed to permit a more complete characterization of the antigens targeted by CD8+ T cells in the NOD mouse model, which will increase its utility in optimizing therapies and exploring the immunopathogenesis of T1D. Retroviral transduction of bone marrow stem cells will be used to rapidly generate NOD mice expressing T cell receptors from early insulitic ( cell-cytotoxic CD8+ T cell clones of unknown specificity. These mice will be used as a T cell source for antigen discovery. In summary, our work will facilitate the development of strategies to interfere with pathogenic T cell populations, as well as assays to monitor autoimmune activity. Relevance in lay language: ( cells in the pancreas make insulin, which is essential for controlling how sugar is used in the body. Type 1 diabetes occurs when the immune system kills the ( cells and insulin can no longer be made. The proposed work will identify the molecular targets of the destructive immune cells and develop methods to monitor and control their activity.