CD8 T Cell Reactivity to IGRP as an Autoimmunity Marker in Type 1 Diabetes

描述(申请人提供)：1型糖尿病(T1D)是一种以T细胞介导的胰岛β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，β细胞毒性CD8+T细胞是导致T1D的β细胞破坏的重要参与者。CD8+T细胞也被怀疑是患者消除β细胞的贡献者。我们发现一种来源于胰岛特异性葡萄糖-6-磷酸酶催化亚单位相关蛋白(IGRP)的多肽是NOD小鼠中普遍存在的CD8+T细胞的靶标。鉴于NOD小鼠和人类T1D之间的相似性，我们假设IGRP反应性CD8+T细胞将像NOD小鼠一样对T1D患者的β细胞根除做出重要贡献。为了开始将我们的发现应用于患者，我们使用转人类I类MHC分子HLA-A*0201的NOD小鼠来鉴定T细胞在T1D自发发育过程中靶向的HLA-A*0201结合IGRP多肽。使用未免疫的人类白细胞抗原转基因小鼠的胰岛浸润性T细胞鉴定的反应性既是自发发生的，也是与疾病相关的。因此，这些多肽是探索人类T1D患者T细胞靶点的极佳候选者。虽然HLA-A*0201是一种常见的I类MHC分子，但阐明在其他人类I类分子的背景下识别的IGRP肽将使那些可以受益于基于肽的预测、诊断和治疗策略的开发能够更广泛地覆盖人群。为此，我们产生了三个新的NOD株，分别表达人类白细胞抗原-A*1101、人类白细胞抗原B*0702或人类白细胞抗原-Cw*0304。这些人类白细胞抗原分子代表三种不同的人类白细胞抗原超型，而人类白细胞抗原-A*0201代表第四种超型。当所有四种超类型都被瞄准时，人口覆盖率可以达到大约90%。我们将从人类白细胞抗原转基因小鼠中分离胰岛浸润性T细胞，并确定在不同的人类白细胞抗原分子中识别的IGRP多肽。然后，我们将检验T1D患者的T细胞将识别相同的多肽的假设。考虑到IGRP作为自身免疫反应靶点的重要性，我们假设CD8+T细胞对IGRP的反应也将作为人类β细胞特异性自身免疫活动的标志。监测这些T细胞反应可以评估介入治疗的免疫学影响，并比目前可能的情况更早地检测自身免疫活性。外行语言的相关性：拟议的工作可能会导致新的测试，以确定有患T1D风险的个人。还可以开发测试来监测正在接受治疗的患者的破坏性T细胞活动，以便医生能够知道治疗是否有效。

DESCRIPTION (provided by applicant): Type 1 diabetes (T1D) is an autoimmune disease characterized by T cell-mediated destruction of the pancreatic islet beta cells. Studies of the nonobese diabetic (NOD) mouse model of the disease have shown that beta cell-cytotoxic CD8+ T cells are essential participants in the beta cell destruction that leads to T1D. CD8+ T cells are also suspected contributors to beta cell elimination in patients. We identified a peptide derived from islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) as the target of a prevalent population of pathogenic CD8+ T cells in NOD mice. In light of the similarities between T1D in NOD mice and humans, we hypothesize that IGRP-reactive CD8+ T cells will be important contributors to beta cell eradication in T1D patients as they are in NOD mice. To begin to translate our findings to patients, we used NOD mice transgenic for the human class I MHC molecule HLA-A*0201 to identify HLA-A*0201-binding IGRP peptides targeted by T cells during the spontaneous development of T1D. Reactivities identified using islet-infiltrating T cells from unimmunized HLA-transgenic mice are both spontaneously occurring and disease-relevant. Thus, these peptides represent excellent candidates for exploration as targets of T cells in human T1D patients. While HLA-A*0201 is a common class I MHC molecule, elucidation of the IGRP peptides recognized in the context of other human class I molecules would allow wider coverage of the population in terms of those that could benefit from the development of peptide- based predictive, diagnostic, and therapeutic strategies. To this end, we have generated three new NOD strains expressing HLA-A*1101, HLA-B*0702, or HLA-Cw*0304. These HLA molecules are representative of three different HLA supertypes, while HLA-A*0201 is representative of yet a fourth. Coverage of the population can be approximately 90% when all four supertypes are targeted. We will isolate islet-infiltrating T cells from the HLA-transgenic mice and determine the IGRP peptides recognized in the context of the different HLA molecules. We will then test the hypothesis that the same peptides will be recognized by T cells from T1D patients. Given the importance of IGRP as a target of the autoimmune response in both standard and HLA-A*0201-transgenic NOD mice, we hypothesize that CD8+ T cell responses to IGRP will also serve as markers for beta cell-specific autoimmune activity in humans. Monitoring of these T cell responses may permit assessment of the immunological impact of intervention therapies and allow earlier detection of autoimmune activity than is currently possible. Relevance in lay language: The proposed work may lead to new tests to identify individuals at risk of developing T1D. Tests may also be developed to monitor destructive T cell activity in patients undergoing treatment, so that doctors will be able to know if the treatments are working.