Antigens Recognized by CD8+ T Cells in Type 1 Diabetes

描述（由申请人提供）：1型糖尿病（T1 D）是一种自身免疫性疾病，其特征在于T细胞介导的胰岛（细胞）破坏。对非肥胖糖尿病（NOD）小鼠模型的研究表明，CD 8 + T细胞是T1 D发展所必需的。我们使用从NOD小鼠中分离的细胞毒性CD 8 + T细胞克隆来鉴定早期胰岛T细胞的两个抗原靶标。这些是胰岛特异性葡萄糖-6-磷酸酶催化亚基相关蛋白（IGRP）和肌强直性肌营养不良症激酶（DMK）。与第三种已知的早期胰岛CD 8 + T细胞靶点（即，胰岛素），这三种特异性可以共同占NOD小鼠中高达一半的胰岛浸润性CD 8 + T细胞。在这里，我们将通过使用来自HLA转基因NOD小鼠的胰岛浸润T细胞来绘制这些细胞抗原的表位，将我们的发现转化为人类T1 D，这些细胞抗原被HLA-A*0201限制性T细胞靶向。然后将评估HLA-A*0201阳性患者和HLA转基因小鼠将表现出关于它们识别的表位的重叠特异性的假设。接下来，我们新开发的通过内吞受体DEC-205将细胞抗原递送到稳态树突状细胞（DC）的能力将允许我们测试这种治疗将导致CD 8 + T细胞耐受和疾病改善的假设。我们将研究靶向一种IGRP衍生肽的DC对转移的和内源性IGRP反应性CD 8 + 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，包括我们设计用于检测体内IGRP特异性T细胞细胞毒性的细胞毒性测定。这些研究选择了IGRP，因为它是NOD小鼠中非常重要的CD 8 + T细胞抗原。最后，一个“高通量”的抗原发现的方法将被采用，以允许一个更完整的表征由CD 8 + T细胞在NOD小鼠模型，这将增加其效用，在优化治疗和探索免疫发病机制的T1 D靶向的抗原。骨髓干细胞的逆转录病毒转导将用于从早期胰岛细胞毒性CD 8 + T细胞克隆中快速产生表达T细胞受体的NOD小鼠，所述细胞克隆的特异性未知。这些小鼠将用作抗原发现的T细胞来源。总之，我们的工作将促进策略的发展，以干扰致病性T细胞群，以及检测，以监测自身免疫活性。 用外行的话来说：（胰腺中的细胞产生胰岛素，这对控制体内糖的使用至关重要。1型糖尿病发生时，免疫系统杀死（细胞和胰岛素不能再制造。拟议的工作将确定破坏性免疫细胞的分子靶点，并开发监测和控制其活性的方法。

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.