TCR Transduced CD8+ T Cells for Adoptive Immunotherapy

抗原特异性TCR转导淋巴细胞用于过继免疫治疗的概念正在获得越来越多的支持。然而，为了使这成为现实，必须仔细描述这些细胞对宿主环境的生物学和体内反应，包括耐受性、抗原呈递和肿瘤微环境。我们的转化研究小组最近开发了一系列新的观察/试剂来解决这个问题。首先，我们观察到环磷酰胺（CTX）预处理诱导PBL中DC淋巴细胞减少后扩张。其次，我们已经描述了IL-12在体外启动过程中的调节能够促进早期效应（TEA）样表型的获得。两者都与体内增强的抗肿瘤反应有关。第三，我们的项目合作者（Shikar Mehrotra博士）成功地创造了一种TCR转基因小鼠（称为h3T），它在外周CD8+ T细胞中表达功能性黑色素瘤抗原（酪氨酸酶）特异性的人类TCR，从而提供了一种表达酪氨酸酶特异性TCR和TCR转导的相同特异性T细胞的原始内源性T细胞来源。我们推测，将TCR转导的CD8+ T细胞的抗原特异性反应与促进DC功能的环境相结合，将产生更有效的抗肿瘤免疫。特异性目的1将定义稳态增殖和IL-12调节对肿瘤宿主中TCR转导的T细胞存活和功能的影响。然后，我们将评估IL-12调节对TCR转导和h3T转基因T细胞存活的影响机制，特别是通过CTLA-4， PD-1信号传导。特异性目标2将定义TCR转导的CD8+ T细胞在促进DC功能的环境中对抗原呈递的反应，评估DC环境的淋巴细胞减少后的扩张，以及CD8+抗体耗竭后的有限淋巴细胞减少。来自I期临床试验的PBL将用于确认我们的临床前数据。最后，Specific Aim 3将确定在荷瘤环境中诱导TCR转导CD8+ T细胞反应所需的最佳条件，评估体内TCR转导CD8+ T细胞反应的影响机制。然后，我们将确定TCR转导T细胞过继转移到荷瘤小鼠的治疗效果。利用这些新工具来探索TCR转导的T细胞对宿主环境的体内反应机制，将提供设计更有效的过继免疫治疗方案的能力。

The concept of antigen specific TCR transduced lymphocytes for adoptive immunotherapy is gaining increasing support. For this to become a reality, however, the biology and in vivo response of these cells to the host environment, including tolerance, antigen presentation, and tumor microenvironment will have to be carefully delineated. Our translational research group recently has developed a series of novel observations/reagents to address this issue. First, we have observed that cyclophosphamide (CTX) preconditioning induces post-lymphopenia expansion of DC in the PBL. Second, we have delineated that IL-12 conditioning during in vitro priming is able to promote the acquisition of an early effector (TEA) like phenotype. Both are associated with enhanced anti-tumor responses in vivo. Third, our program collaborator (Dr. Shikar Mehrotra) has successfully created a TCR transgenic mouse (termed h3T) which expresses functional melanoma antigen (tyrosinase) specific human TCR in peripheral CD8+ T cells thus providing a source of naive endogenous T cells expressing tyrosinase specific TCR and TCR transduced T cells of the same specificity. We hypothesize that combining the antigen specific response of TCR transduced CD8+ T cells with an environment which promotes DC function will result in the generation of more effective anti-tumor immunity. Therefore, we propose the following: Specific Aim 1 will define the impact of homeostatic proliferation and mechanisms of IL-12 conditioning on TCR transduced T cell survival and function in a tumor bearing host. We will then assess the mechanisms by which IL-12 conditioning impacts on TCR transduced and h3T transgenic T cell survival looking specifically at CTLA-4, PD-1 signaling. Specific Aim 2 will define the TCR transduced CD8+ T cell response to antigen presentation in an environment which promotes DC function evaluating both the post-lymphopenia expansion of DC environment, and also with a limited lymphopenia post CD8+ antibody depletion. PBL from the phase I clinical trial will be used to confirm our preclinical data for both aims. Finally, Specific Aim 3 will determine the optimal conditions required to induce a robust memory TCR transduced CD8+ T cell response in a tumor bearing environment evaluating the mechanisms affecting in vivo TCR transduced CD8+ T cells responses We will then define the therapeutic efficacy of TCR transduced T-cells adoptively transferred into a tumor bearing mouse. Using these novel tools to probe the mechanisms involved in the in vivo response of TCR transduced T cells to the host environment should provide an ability to design more effective adoptive immunotherapy protocols.