TCR TRANSDUCED CDB T CELLS FOR ADOPTIVE IMMUNOTHERAPY

抗原特异性TCR转导的淋巴细胞用于过继免疫治疗的概念正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。我们的翻译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，我们已经观察到环磷酰胺（CTX）预处理诱导淋巴细胞减少后在PBL中的DC扩增。第二，我们已经描述了在体外引发期间IL- 12调节能够促进早期效应子（TEA）样表型的获得。两者都与增强的体内抗肿瘤反应有关。第三，我们的项目合作者（Shikar Mehrotra博士）已经成功地创建了TCR转基因小鼠（称为h3 T），其在外周CD 8 + T细胞中表达功能性黑素瘤抗原（酪氨酸酶）特异性人TCR，从而提供了表达酪氨酸酶特异性TCR的初始内源性T细胞和具有相同特异性的TCR转导的T细胞的来源。我们假设，将TCR转导的CD 8 + T细胞的抗原特异性应答与促进DC功能的环境相结合将导致产生更有效的抗肿瘤免疫。因此，我们提出以下建议：具体目标1将定义稳态增殖的影响和IL-12调节TCR转导的T细胞的存活和功能在荷瘤宿主中的机制。然后，我们将评估IL-12调节对TCR转导和h3 T转基因T细胞存活的影响机制，特别是CTLA-4、PD-1信号传导。具体目标2将定义TCR转导的CD 8 + T细胞对促进DC功能的环境中的抗原呈递的应答，评价DC环境的淋巴细胞减少后扩增以及CD 8+抗体耗竭后的有限淋巴细胞减少。I期临床试验的PBL将用于确认我们两个目标的临床前数据。最后，具体目标3将确定在荷瘤环境中诱导稳健的记忆TCR转导的CD 8 + T细胞应答所需的最佳条件，评估影响体内TCR转导的CD 8 + T细胞应答的机制。然后，我们将定义过继转移到荷瘤小鼠中的TCR转导的T细胞的治疗功效。使用这些新的工具来探测TCR转导的T细胞对宿主环境的体内应答中涉及的机制应该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.