CD40-Induced TCR Revision: A Mechanism for Autoimmunity

描述（由申请人提供）：本申请的目的是解决CD 40 + T细胞的发育、CD 40在T细胞受体（TCR）修正中的作用以及诱导的TCR修正如何影响自身免疫。CD 40在包括1型糖尿病（T1 D）在内的自身免疫性疾病中具有直接作用。我们发现效应T细胞的独特亚群，描述为CD 410 CD 40+，在T1 D中是高致病性的。CD 40存在于致糖尿病性T细胞克隆上，并且原代CD 410 CD 40 + T细胞在NOD小鼠中与胰岛炎同时扩增。重要的是，CD 4loCD 40 + T细胞容易将T1 D转移至NOD.scid受体。在机制上，CD 40诱导T细胞中的RAG 1/RAG 2重组机制。在该诱导之后，发生TCR修正，即TCR表达的诱导改变。发现一些修改后的原代T细胞具有高致病性。然而，CD 40诱导的TCR修订可作为已建立的致糖尿病T细胞克隆的功能耐受机制。具体地，CD 40与致糖尿病T细胞克隆BDC2.5接合严重消除了克隆的疾病转移能力。我们发现，在3周龄的NOD小鼠中阻断CD 40-CD 154（CD 40的配体）相互作用不仅可以防止T1 D发作，还可以防止CD 4loCD 40+自身攻击细胞的扩增。在本申请中，我们将探索CD 40如何影响独特的T细胞群。我们的假设是，TCR修订直接影响T细胞耐受性。具体目标#1：CD 4loCD 40 + T细胞是否包含独特的T细胞亚群或代表T细胞内的瞬时活化状态？如果CD 40在T细胞上被诱导，那么这些T细胞与固有的CD 40 T细胞亚群相比是否存在差异？我们计划实验来解决这个核心问题。具体目标#2：CD 40接合如何影响CD 4loCD 40 + T细胞中的TCR修订？自身免疫性疾病和非自身免疫性疾病对CD 40结合的反应是否存在差异？我们将探讨RAG 1和RAG 2的诱导，TCR修订的动力学以及不同来源的CD 154在自身免疫与非自身免疫小鼠中如何影响这一过程。具体目标#3：CD 40接合如何影响T细胞抗原特异性？我们将探讨如何诱导TCR修订影响T细胞抗原特异性使用体外和体内模型。这些拟议的研究不仅解决了潜在的自身攻击性T细胞的发展，但将提供重要的信息，无论是诱导的TCR修订是致病性或致耐受性。

DESCRIPTION (provided by applicant): The goals of this application are to address the development of CD40+ T cells, the role that CD40 plays in T cell receptor (TCR) revision and how induced TCR revision impacts autoimmunity. CD40 has a direct role in autoimmune diseases including type 1 diabetes (T1D). We discovered that a unique subset of effector T cells, described as CD4loCD40+, are highly pathogenic in T1 D. CD40 is present on diabetogenic T cell clones and primary CD4loCD40+ T cells expand concurrently with insulitis in NOD mice. Importantly, CD4loCD40+ T cells readily transfer T1D to NOD.scid recipients. Mechanistically, CD40 induces the RAG1/RAG2 recombination machinery in T cells. Following that induction, TCR revision, induced alteration of TCR expression, occurs. Some revised primary T cells were found to be highly pathogenic. However, CD40 induced TCR revision could serve as a functional tolerance mechanism of established diabetogenic T cell clones. Specifically, CD40 engaging the diabetogenic T cell clone BDC2.5 severely ablated disease transfer ability of the clone. We showed that blocking CD40 - CD154 (the ligand for CD40) interaction in NOD mice at 3-weeks of age prevents not only T1D onset, but prevents expansion of CD4loCD40+, autoaggressive cells. In this application we will explore how CD40 affects the unique T cell population. Our hypothesis is that TCR revision directly impacts T cell tolerance. Specific Aim #1: Do CD4loCD40+ T cells comprise a unique T cell subset or represent a transient activation state within T cells? If CD40 is induced on T cells are there differences in those T cells compared to the intrinsic CD40 T cell subset? We plan experiments to address this central concern. Specific Aim #2: How does CD40 engagement affect TCR revision in CD4loCD40+ T cells? Are there differences in response to CD40 engagement between autoimmune and non-autoimmune conditions? We will explore RAG1 and RAG2 induction, kinetics of TCR revision and how different sources of CD154 in autoimmune versus non-autoimmune mice affect this process. Specific Aim #3: How does CD40 engagement affect T cell antigen specificity? We will explore how induced TCR revision affects T cell antigen specificity using in vitro and in vivo models. These proposed studies address not only the development of potential autoaggressive T cells but will provide important information as to whether induced TCR revision is pathogenic or tolerogenic.