Jo-1-specific T Cell Responses in Polymyositis

描述（由申请人提供）： 多发性肌炎是一种自身免疫性疾病，其中肌肉不适当地靶向T细胞介导的破坏。由于抗原触发物仍然未知，目前的治疗是非特异性的，并且依赖于全局免疫抑制。多发性肌炎存在不同的临床亚型，其由针对特异性核和细胞质抗原（包括Jo-1（组氨酰-tRNA合成酶））的抗体定义。基于一系列遗传学、血清学和组织形态学数据，该提议的基本假设是针对Jo-1的抗原特异性T细胞应答促进抗Jo-1抗体形成以及Jo-1+多发性肌炎中T细胞介导的肌细胞溶解/功能障碍。本研究的初始阶段将确定对Jo-1的体外T细胞增殖和细胞因子应答。随后的实验将涉及从Jo-1 +多发性肌炎患者和健康对照的外周血中克隆Jo-1特异性T细胞。TCR测序以及使用Jo-1片段和线性肽的表位作图研究将允许进一步表征Jo-1特异性T细胞库，并促进来自多发性肌炎患者和健康对照的Jo-1特异性T细胞的比较。这些Jo-1特异性T细胞亚群在体内病变肌肉淋巴细胞浸润的定位将通过RT-PCR和免疫组织化学技术进行研究。肌肉浸润淋巴细胞的克隆将提供一个抗原特异性细胞池，用于分析对Jo-1以及其他来自肌肉蛋白提取物的推定自身抗原的反应。在体外将Jo-1特异性T细胞应用于自体肌管培养物后对肌细胞破坏的评估将进一步确定此类T细胞在Jo-1+多发性肌炎中的作用。这些研究还旨在提供关于改变的T细胞库和抗原呈递在Jo-1+多发性肌炎表达中的相对作用的见解。

DESCRIPTION (provided by applicant): Polymyositis represents an autoimmune disease in which muscle is inappropriately targeted for T cell-mediated destruction. Because the antigenic trigger(s) remain unknown, current therapies are non-specific and rely on global immunosuppression. Distinct clinical subsets of polymyositis exist that are defined by antibodies directed against specific nuclear and cytoplasmic antigens including Jo-1 (histidyl-tRNA synthetase). Based on a range of genetic, serologic, and histomorphologic data, the underlying hypothesis of this proposal is that antigen-specific T cell responses directed against Jo-1 promote anti-Jo-1 antibody formation as well as T cell-mediated cytolysis/dysfunction of muscle cells in Jo-1+ polymyositis. , The initial phase of this study will define the in vitro T cell proliferative and cytokine responses to Jo-1. Subsequent experiments will involve cloning of Jo-1-specific T cells derived from the peripheral blood of patients with Jo-1 + polymyositis and healthy controls. TCR sequencing as well as epitope mapping studies using both Jo-1 fragments and linear peptides will then permit further characterization of the Jo-1-specific T cell repertoire and facilitate comparison of Jo-1-specific T cells derived from polymyositis patients and healthy controls. Localization of these Jo-1-specific T cell subsets to lymphocytic infiltrates of diseased muscle in vivo will be investigated through RT-PCR and immunohistochemistry techniques. Cloning of muscle-infiltrating lymphocytes will provide a pool of antigen-specific cells to be analyzed for responses to Jo-1 as well as other putative autoantigens derived from muscle protein extracts. Assessment of myocyte destruction after the application of Jo-1-specific T ceils to autologous myotube cultures in vitro will further define the role of such T cells in Jo-1+ polymyositis. These studies are intended to also provide insight concerning the relative roles of altered T cell repertoire and antigen presentation in the expression of Jo-1+ polymyositis.