A Study of the Selection and Peripheral Function of Human Insulin-Reactive T-cells in a Type 1 Diabetic Immune System

项目摘要 在1型糖尿病(T1D)中，β细胞抗原反应性T细胞逃避胸腺的负选择，旅行到 并杀死产生胰岛素的胰岛β细胞。在健康个体中，中枢和外周 免疫耐受机制可防止这种类型的自身免疫攻击。目前尚不清楚哪种容忍度 在T1D的情况下失败。将来自T1D患者的胰岛素反应性T细胞受体(TCR)引入 人源化小鼠的外周可以引发糖尿病，这与自身反应性T细胞逃逸的概念一致 从消极选择中选择会引发疾病。另一方面，β细胞抗原反应性T细胞也 从健康对照(HC)个体的血液中分离出来，增加了外周血细胞缺陷的可能性 耐受机制可能促进T1D。遗传学研究已经确定了40多个T1D风险变异，包括 涉及中枢和外周耐受机制的基因。我们假设两者都有 T1D患者中造血干细胞(HSC)固有和胸腺固有的遗传变异 导致糖尿病患者T细胞发育过程中致糖尿病T细胞受体阴性选择失败 以及，附加地或可替换地；b)改变自身反应性T细胞的特性以增加 它们的糖尿病致死性。我们已经建立了一种个性化免疫(PI)小鼠模型，允许我们 在免疫缺陷NOD/LtSz-SCID IL2Rγ缺失小鼠体内产生成人免疫系统 (NSG)接受患者HSC和部分相合的胎儿胸腺移植的小鼠。我们还展示了 患者的HSCs可以被慢病毒转导以表达特定的TCR，并随后用于 在胸腺器官培养实验中重建NSG小鼠或人胸腺组织。使用这些技术和使用 获取T1D和HC供者的HSC和胸腺组织，我们将研究胸腺的选择和后续 T1D造血干细胞来源的T细胞表达的胰岛素反应性TCR的外周功能 胸腺。在这些研究中，我们的目标是确定在大脑中央是否存在遗传决定的缺陷。 T1D的耐受机制为负选择和/或外周免疫耐受。

Project Summary In Type 1 diabetes (T1D), beta cell antigen-reactive T-cells escape negative selection in the thymus, travel to the periphery, and kill insulin-producing pancreatic beta cells. In healthy individuals, central and peripheral immune tolerance mechanisms prevent this type of autoimmune attack. It is not known which level of tolerance fails in cases of T1D. Introduction of an insulin-reactive T-cell receptor (TCR) derived from a T1D patient to the periphery of humanized mice can initiate diabetes, consistent with the notion that escape of autoreactive T-cells from negative selection promotes disease. On the other hand, beta cell antigen-reactive T-cells have also been isolated from the blood of healthy control (HC) individuals, raising the possibility that defective peripheral tolerance mechanisms may promote T1D. Genetic studies have identified over 40 risk variants for T1D, including genes implicated in both central and peripheral tolerance mechanisms. We hypothesize that there are both hematopoietic stem cell (HSC)-intrinsic and thymus-intrinsic genetic variants in T1D individuals that a) lead to the failure of negative selection of diabetogenic T-cell receptors during T-cell development in the thymus and, additionally or alternatively; b) alter the characteristics of autoreactive T-cells to increase their diabetogenicity. We have established a Personalized Immune (PI) mouse model that allows us to generate an adult human's immune system de novo in immunodeficient NOD/LtSz-scid IL2R gamma null mice (NSG) mice receiving patient HSCs and a partially HLA-matched fetal thymus graft. We have also demonstrated that the patient HSCs can be lentivirally transduced to express a specific TCR and subsequently used to reconstitute NSG mice or human thymus tissue in thymic organ culture assays. With these techniques and with access to HSC and thymus tissue from T1D and HC donors, we will study the thymic selection and subsequent peripheral function of insulin-reactive TCRs expressed on T-cells derived from T1D HSCs and selected in a T1D thymus. In these studies, we aim to determine if there is a genetically-predetermined defect in the central tolerance mechanism of negative selection and/or peripheral immune tolerance mechanisms in T1D.