Identification of the cognate epitopes of autoreactive T cells in Type 1 Diabetes

摘要 1型糖尿病(T1D)影响着全球约400万人，其中包括160万美国人。 T1D是由胰腺细胞的进行性破坏引起的，导致 产生胰岛素。渗入胰岛的CD_8~+、CD_4~+细胞介导的细胞 通过识别呈现在I类和II类MHC上的多肽表位，以抗原特异性的方式破坏 分别是分子。相反，调节性T细胞可以抑制糖尿病T细胞，从而防止T1D 发病机制。识别细胞呈递的表位对于这些自身反应性T细胞的功能至关重要 细胞。仅有少量自身表位被自身反应性CD8+、CD4+效应器和调节性T细胞识别 T1D中的细胞已经被发现。然而，大多数胰岛浸润性T细胞识别的表位 都是未知的。对这些表位的了解对于理解疾病的发病机制和 开发有针对性的疗法。目前，T细胞抗原发现的广泛适用和有效的方法 缺乏揭示自身反应的能力。这个项目的首要目标是揭示 在T1D中使用我们开发的一种新的可推广的抗原发现技术的自身反应性T细胞 一群人。在这个方案中，我们将使用信号和抗原呈递来发现T细胞表位 识别小鼠效应性和调节性T细胞识别表位的双功能受体(SABRs) T1D模型，NOD小鼠。我们建议构建一个由表达的基因衍生的表位的文库 特别是在胰腺细胞中，将导致识别新的胰岛浸润性T细胞靶点。我们会 从已发表的质谱学和NOD小鼠基因表达数据集构建表位文库。 我们将通过对NOD小鼠的胰岛进行单细胞TCR测序来获得胰岛反应性TCRs。 利用细胞来源的SABR文库，我们将确定胰岛反应性TCR的同源表位并验证 它们在体外。这些研究确定的表位将导致未来的研究，旨在了解 自身反应性T细胞破坏免疫耐受并开发靶向免疫治疗方法 战斗T1D。该方法还将为发现T1D患者T细胞的抗原奠定基础 与人类小岛研究网络有联系的样本。 1

ABSTRACT Type 1 Diabetes (T1D), affects approximately 4 million individuals worldwide, including 1.6 million Americans. T1D is caused by progressive destruction of pancreatic  cells, resulting in a significantly diminished capacity to produce insulin. Diabetogenic CD8+ and CD4+ effector T cells that infiltrate pancreatic islets mediate  cell destruction in an antigen-specific manner by recognizing peptide epitopes presented on class I and class II MHC molecules respectively. In contrast, regulatory T cells can suppress diabetogenic T cells, thereby preventing T1D pathogenesis. Recognition of epitopes presented by  cells is critical for the function of these autoreactive T cells. Only a small number of self-epitopes recognized by autoreactive CD8+, CD4+ effector and regulatory T cells in T1D have been uncovered. However, the epitopes recognized by the majority of islet-infiltrating T cells are not known. The knowledge of these epitopes is critical for understanding disease pathogenesis and for developing targeted therapies. Currently, widely applicable and efficient methods for T cell antigen discovery for uncovering autoreactivity are lacking. The overarching goal of this project is to uncover the cognate epitopes of autoreactive T cells in T1D using a novel and generalizable antigen discovery technology developed by our group. In this proposal, we will employ T cell epitope discovery using Signaling and Antigen-presenting Bifunctional Receptors (SABRs) to identify the epitopes recognized by effector and regulatory T cells in a mouse model of T1D, NOD mice. We propose that constructing a library of epitopes derived from genes expressed specifically in pancreatic  cells will lead to identification of novel targets of islet-infiltrating T cells. We will construct epitope libraries from published mass spectrometry and gene expression datasets from NOD mice. We will obtain islet-reactive TCRs by performing single cell TCR sequencing on pancreatic islets of NOD mice. Using  cell derived SABR libraries, we will determine the cognate epitopes of islet-reactive TCRs and validate them in vitro. The epitopes identified by these studies will lead to future studies aiming to understand the breakage of immune tolerance by autoreactive T cells and to develop targeted immunotherapy approaches to combat T1D. This approach will also establish the foundation for antigen discovery for T cells from T1D patient samples in affiliation with Human Islet Research Network. 1