Modifying T Cell Responses by Combinatorial Targeting of Negative regulators

描述（由申请人提供）：当被持久性抗原长时间刺激时，T细胞通常失去其继续产生稳健应答的能力。这是一个重要的问题，因为已建立的肿瘤和慢性感染也可以通过诱导抗原特异性T细胞中类似的耐受状态（称为衰竭或无反应性）来逃避保护性免疫反应。该项目确定了有助于维持这种耐受性的新型调节分子。耐受性的分子机制被理解为包括抑制T细胞中不同细胞内激活信号的抑制性分子如PD 1、LAG3、CTLA 4等的表达。因此，最近的临床研究已经成功地使用针对这些负调节因子的抗体和抑制剂来增强T细胞对肿瘤和慢性病毒感染的应答。该提案评估了两种新鉴定的调节剂PEAR1和EndoD1协同抑制CD4 + T细胞的反应性，从而促进T细胞耐受性的假设。据预测，抑制T细胞中的这些分子可以提高免疫疗法的功效，例如针对肿瘤-甚至可能在单独靶向已知调节剂不足的情况下。这些假设将使用三个独立和互补的目标进行评估。1.通过使用T细胞特异性敲低方法，确定这些新型调节剂如何单独和协同地影响体内自身免疫和移植物排斥背景下的T细胞活化。除了关节炎模型中的初步数据外，还将通过列举活化标志物表达、细胞因子产生以及免疫病理学来评价皮炎模型中敲减对T细胞的影响。2.阐明这些调节剂在耐受性T细胞中的生物化学靶点，以期开发一种合理的策略，以确定可以最有效地靶向免疫治疗的途径的排列。分子分析和计算建模的组合将用于此目的。3.在肿瘤的过继性T细胞治疗过程中，通过敲低这些调节因子在肿瘤特异性转基因T细胞以及天然肿瘤浸润淋巴细胞中的表达来确定靶向这些调节因子的策略。预计这些实验将首次确定T细胞表达的PEAR 1和EndoD1作为T细胞效应子应答抑制剂的作用。这是重要的，因为它提供了治疗性的新靶点（a）在对肿瘤和慢性感染的免疫的背景下增强抗原特异性T细胞的功能，或 (b)在自身免疫和移植排斥期间耐受T细胞。此外，关于这些分子与其他已知的T细胞活化负调控因子（如PD1、CTLA4、cbl-b和LAG3）的协同性的拟议研究将产生快速整合这些靶点所需的数据。一个合理的策略，以指导设计这样的combinatoria治疗，使用生化数据和计算模型，因此，也包括在建议。

DESCRIPTION (provided by applicant): T cells often lose their ability to continue making robust responses, when stimulated for a long time by a persistent antigen. This is a significant problem, because established tumors and chronic infections can also evade protective immune responses by inducing a similar state of tolerance in antigen-specific T cells - known as exhaustion or anergy. This project identifies novel regulatory molecules that help maintain such a tolerance. The molecular mechanics of tolerance is understood to include the expression of inhibitory molecules such as PD1, LAG3, CTLA4 etc. which dampen different intracellular activating signals in T cells. Accordingly, recent clinical studies have successfully used antibodies and inhibitors against such negative regulators to augment T cell responses to tumors and chronic viral infections. This proposal evaluates the hypothesis that two newly identified regulators - PEAR1 and EndoD1 - cooperatively inhibit the responsiveness of CD4+ T cells, contributing to T cell tolerance. It is projected that inhibiting these molecules in T cellscan improve the efficacy of immunotherapy, e.g. against tumors - potentially even in contexts where targeting known regulators alone is insufficient. These hypotheses will be evaluated using three independent and complimentary aims. 1. Determine how these novel regulators individually and synergistically affect T cell activation in vivo in the context of autoimmunity and graft rejection by using a T cell-specific knockdown approach. In addition to preliminary data in an arthritis model, the impact of the knockdowns on T cells in a dermatitis model will be evaluated by enumerating activation marker expression, cytokine production as well as immunopathology. 2. Elucidate the biochemical targets of these regulators in tolerant T cells, with a view to developing a rational strategy to identify permutations of pathways that can be most efficiently targeted for immunotherapy. A combination of molecular analyses and computational modeling will be used for this purpose. 3. Define a strategy to target these regulators during adoptive T cell therapy for tumors by knocking-down their expression in tumor-specific transgenic T cells as well as native tumor-infiltrating lymphocytes. It is expected that these experiments will, for the first time, define the role of T cell expressed PEAR1 and EndoD1 as inhibitors of T cell effector responses. This is significant because it offers new targets for therapeutically (a) enhancing the function of antigen-specific T cells in the context of immunity to tumors and chronic infections or (b) tolerising T cells during autoimmunity and graft rejection. Furthermore, the proposed studies on the cooperativity of these molecules with other known negative regulators of T cell activation, such as PD1, CTLA4, cbl-b and LAG3, will generate data required to rapidly integrate these targets with ongoing clinical efforts. A rational strategy to guide the design of such combinatoria treatments, using biochemical data and computational models, is therefore also included in the proposal.