Receptor Diversity in Recognition of Influenza HA

这个项目的长期目标是使用一个特征良好的模型系统来定义流程 管理对自身抗原的耐受性和自身免疫力。为此，我们开发了转基因小鼠 表达流感病毒血凝素(HA)作为名义上的自身抗原，并一直在分析 它们诱导CD4+T和B细胞对HA耐受的程度和基础。在最近的一次融资中 期间，我们发现由MHC Class II启动子驱动表达HA的小鼠(HACII小鼠)并共同表达 HA特异性的CD4+T细胞受体(TCRxHACII小鼠)自发产生自身免疫， 炎症性关节炎作为突出的疾病表现。我们证明了抗体不是必需的 关节炎的发生，以及增加CD4+T细胞表达 转基因TCR使关节炎发展得更快。此外，关节炎的外显性可能是 通过改变TCR对HA的反应性来调节，因为在大多数小鼠中，TCR 将HA识别为激动肽(TSIxHACII小鼠)患上关节炎，而表达TCR的小鼠 HA(TS1(Sw)xHACII小鼠)的反应性降低了约100倍，患关节炎的几率大大降低 洞察力。该提案将使用此模型系统来了解自动反应之间的相互作用 由系统分布的抗原提呈细胞(APC)表达的CD4+T细胞和自体多肽可以 导致炎症性关节炎的发展。在目标1中，我们将研究分子和细胞 控制TCRxHACII关节炎小鼠自身反应性CD4+T细胞发育的过程。我们将定义 伴随或先于关节炎发展的自身反应性CD4+T细胞表型的变化，以及 确定不同的过程(如外周扩张、效应细胞分化)对 自身反应性CD4+T细胞引起关节炎的能力。在目标2中，我们将研究HA是如何在 不同的APC亚群有助于TCRxHACII小鼠关节炎的发展。我们将鉴定表型 与关节炎发生相关的MHC Class 11+细胞的变化，并检查自身反应 CD4+T细胞的发育是由不同数量的自身抗原的表达和/或由不同的 APC类型。在目标3中，我们将评估扰乱CD4+T细胞：APC相互作用如何影响关节炎 TCRxHACII小鼠的发育。我们将确定如何扰乱CD4+T细胞的激活和/或 分化影响关节炎的发展，并检查感染如何增加外显性 遗传易感人群中的关节炎。这些研究将为我们提供对 免疫谱系形成和耐受的机制，将普遍适用于 自身免疫，并将利用与诊断和治疗直接相关的实验模型 人类类风湿关节炎(RA)。

The long-term goal of this project is to use a well-characterized model system to define processes governing tolerance versus autoimmunity to self antigens. To this end, we have developed transgenic mice expressing the influenza virus hemagglutinin (HA) as a nominal self-antigen, and have been analyzing the extent and basis by which they induce CD4+ T and B cell tolerance to the HA. In the most recent funding period, we showed that mice expressing HA driven by a MHC Class II promoter (HACII mice) and coexpressing HA-specific CD4+ T cell receptors (TCRxHACII mice) spontaneously develop autoimmunity, with inflammatory arthritis as a prominent disease manifestation. We showed that antibody is not required for arthritis development, and that genetic crosses that increased the frequency of CD4+ T cells expressing the transgenic TCR caused arthritis to develop more rapidly. Moreover, the penetrance of arthritis could be modulated by varying the reactivity of the TCR for the HA, since the majority of mice in which the TCR recognizes HA as an agonist peptide (TSIxHACII mice) developed arthritis, whereas mice expressing a TCR with ~100-fold lower reactivity for the HA (TS1(SW)xHACII mice) developed arthritis with substantially lower penetrance. This proposal will use this model system to understand how interactions between autoreactive CD4+ T cells and a self-peptide expressed by systemically distributed antigen presenting cells (APCs) can lead to the development of inflammatory arthritis. In Aim 1 we will examine the molecular and cellular processes governing autoreactive CD4+ T cell development in arthritic TCRxHACII mice. We will define changes in autoreactive CD4+ T cell phenotype that accompany or precede the development of arthritis, and determine how distinct processes (e.g. peripheral expansion, effector cell differentiation) contribute to the ability of autoreactive CD4+ T cells to cause arthritis. In Aim 2 we will examine how expression of HA in different APC subsets contributes to arthritis development in TCRxHACII mice. We will identify phenotypic changes in MHC Class ll+ cells that are associated with arthritis development, and examine how autoreactive CD4+ T cell development is shaped by expression of a self-antigen in differing amounts and/or by different APC types. In Aim 3 we will assess how perturbing CD4+ T cell:APC interaction impacts arthritis development in TCRxHACII mice. We will determine how disrupting CD4+ T cell activation and/or differentiation affects arthritis development, and examine how infections might increase the penetrance of arthritis among genetically susceptible individuals. These studies will provide fundamental insights into the mechanisms of immune repertoire formation and tolerance, will have general applicability to the processes of autoimmunity, and will exploit experimental models with direct relevance to the diagnosis and treatment of human rheumatoid arthritis (RA).