Mechanisms of immune tolerance in autoimmune diabetes

描述(由申请人提供)：1型糖尿病(T1D)是由自身免疫T淋巴细胞介导的胰腺中产生胰岛素的β细胞的破坏所致。每日多次注射胰岛素对糖尿病患者来说是一种挽救生命的疗法，但并不能治愈。为了更好地治愈T1D，我们必须首先识别自身反应性T细胞，其次必须清除它们。直到最近，识别细胞一直是一项非常困难的任务。然而，多肽-MHC四聚体技术的最新进展使我们能够识别、跟踪和询问患有1型糖尿病的小鼠和人类的单个CD4T淋巴细胞克隆。通过拥有研究疾病期间抗原特异性T细胞的工具和技术，我们将能够评估外周耐受性的崩溃，并检查治疗效果，以选择性地清除或沉默这些自我反应性T细胞作为靶向治疗。我们最近采用了一种灵敏的四聚体富集法，允许对一种特殊多肽：MHCII复合体的极其罕见的CD4T细胞进行鉴定和表型鉴定。我们推测，第二类MHC：肽四聚体和浓缩技术将提供一种灵敏和可靠的方法来确定胰岛抗原特异性CD4T细胞的数量和激活状态。 来自T1D患者的可行样本。我们进一步假设，使用这种方法鉴定胰岛抗原特异性的CD4T细胞将为T1D诊断和疾病分期提供有用的生物标志物试剂。利用这项技术，我们将确定糖尿病患者是否会失去外周耐受性，胰岛β细胞多肽表位是否成为免疫系统的主要靶点。我们预测，与非糖尿病患者相比，新发的T1D患者将有更多的β细胞肽：具有活化表型的MHCII特异性CD4T细胞。随着对β细胞靶点的更好了解，我们将能够开发抗原特异性方法来选择性地消除自毁T细胞来治愈糖尿病。

DESCRIPTION (provided by applicant): Type 1 diabetes (T1D) results from the autoimmune T lymphocyte mediated destruction of the insulin producing beta cells in the pancreas. Multiple daily insulin injections are a lifesaving therapy for diabetic patients, they are not a cure. In orer to cure T1D we must first identify the self-reactive T cells, and secondly we must remove them. Until recently identifying the cells has been a very difficult task. However, recent advances in peptide-MHC tetramer technology have allowed us to identify, track and interrogate individual CD4+ T lymphocyte clones in both mouse models and humans with type 1 diabetes. By having the tools and technology to study antigen specific T cells during disease, we will be able to assess the breakdown in peripheral tolerance and examine therapeutic efficacy to selectively remove or silence these self-reactive T cells as a targeted cure. We have recently adapted a sensitive tetramer enrichment protocol allowing the identification and phenotyping of exceedingly rare CD4+ T cells of a specific peptide:MHCII complex. We hypothesize that class II MHC:peptide tetramer and enrichment techniques will provide a sensitive and robust method for determining the number and activation status of islet Ag-specific CD4+ T cells using clinically feasible samples from T1D patients. We further hypothesize that characterization of islet Ag-specific CD4 T cells using this approach will provide a useful biomarker reagent for T1D diagnosis and disease staging. Using this technology we will determine if peripheral tolerance is lost in diabetic patients and islet beta cell peptide epitopes become major targets of the immune system. We predict that individuals with new onset T1D will have more beta cell peptide:MHCII specific CD4+ T cells with an activated phenotype than non-diabetic individuals. With a better understanding of beta cell targets, we will be able to develop antigen specific approaches to selectively eliminate self-destructive T cells to cure diabetes.