TCR Engineered CD4 Cells as Helpers in Tumor Immunity

描述(由申请人提供)：以细胞溶解T淋巴细胞(CTL)反应为中心的癌症主动、特异和过继免疫治疗已显示出令人鼓舞的结果。然而，这些治疗方式将受益于同源的CD4T辅助细胞(Th)的参与。我们发现，CD4T细胞表达MHC-I类黑色素瘤特异性T细胞受体(TCR)，CTL也利用TCR识别该表位--以表位特异的方式合成Th1型细胞因子，显示出对黑色素瘤细胞和替代靶细胞的杀伤能力。我们建议对这种MHC-I类限制性TCR工程的CD4T细胞在抗黑色素瘤免疫反应中的生物学进行全面的研究，重点关注它们作为效应细胞和辅助T细胞的作用。中心假说是：“考虑到帮助和抑制是两种相互对立的条件，如果一个人能够通过相同的TCR和相同的MHC限制分子同时接触识别感兴趣的肿瘤相关表位的CTL和辅助细胞，则CD4T细胞将促进产生强大而持久的CTL反应，并缓解Treg的激活。此外，通过表现出自身的抗肿瘤效应功能，它们将扩大抗肿瘤的曲目”。我们建议通过几个特定的目标来验证这一假设，在体外实验中，通过设计表达黑色素瘤特异性TCR(MART-127-35和Tyrosinase368-376)特异性TCR的CD4T细胞，以及在体内使用由小鼠恒定区和人类可变区组成的人-鼠嵌合体TCR的转基因小鼠。CD4Th细胞的生物学特性将通过在体外CTL生成试验、体外Treg激活试验以及嵌合TCR工程T细胞过继转移到携带A2.1/KB转基因B-16黑色素瘤细胞的HL A-A2.1/KB小鼠中进行全面的表型和功能表征来评估。这项拟议的研究将导致开发一种新的补充策略，以积极开展癌症的特异性和过继免疫治疗。摘要：这项拟议的研究旨在开发一种新的方法，让杀伤T细胞和辅助T细胞(免疫系统中的两个重要角色)以协作和协同的方式工作，以协调针对人类癌症的强大和持久的细胞免疫攻击--癌症是人类死亡的主要原因。公共卫生相关性：“癌症疫苗”和癌症的过继细胞疗法已经显示出令人振奋的结果，但这两种基本方法需要新的战略来解决两个主要障碍--缺乏一种有效的方式，使同源的CD4T辅助(Th)细胞参与治疗和T调节(Treg)细胞的活动。我们提出了一种新的策略，通过使用经工程设计的CD4T细胞来表达MHC I类限制性T细胞受体(TCR)和肿瘤表位特异性T细胞受体(TCR)来解决这两个限制因素，细胞溶解T细胞(CTL)也利用TCR识别肿瘤抗原。因此，TCR工程的CD4Th细胞可以通过减轻Treg活性(因为帮助和抑制是相互对立的条件)和自身的细胞溶解潜力，为产生强大而持久的CTL反应提供“帮助”，并扩大治疗范围。

DESCRIPTION (provided by applicant): Active specific and adoptive immunotherapy for cancer centering on cytolytic T lymphocyte (CTL) response have shown encouraging results. These treatment modalities, however, would benefit from the involvement of cognate CD4+ T helper (Th) cells. We have found that CD4+ T cells -- engineered to express a MHC class I- restricted melanoma epitope specific T cell receptor (TCR) that is also used by CTL to recognize the epitope -- synthesize Th1 type cytokines and exhibit cytolytic potential against melanoma cells and surrogate target cells in an epitope specific manner. We propose a comprehensive study of the biology of such MHC class I-restricted TCR engineered CD4 T cells in an anti-melanoma immune response focusing on their role as effector cells and as helper T cells. The central hypothesis is that "considering that help and suppression are two mutually opposed conditions, if one could engage CTL and helper cells recognizing a tumor associated epitope of interest simultaneously through an identical TCR and on the same MHC restricting molecules, the CD4+ T cells would facilitate the generation of a robust and long-lasting CTL response and mitigate Treg activation. Additionally, by exhibiting anti-tumor effector function of their own, they would expand the anti-tumor repertoire". We propose to test this hypothesis through several specific aims designed with CD4+ T cells engineered to express melanoma epitope (MART-127-35 and Tyrosinase368-376)-specific TCR in in vitro assays, and in HLA- A2.1/Kb transgenic mice employing a chimeric human-mouse TCR consisting of mouse constant regions and human variable regions, in vivo. The biology of the CD4+ Th cells will be assessed through a comprehensive phenotypic and functional characterization in in vitro CTL generation assay, in vitro Treg activation assay, and in adoptive transfers of chimeric TCR engineered T cells into HLA-A2.1/Kb mice bearing A2.1/Kb transgenic B-16 melanoma cells. The proposed research will lead to the development of a new and complementary strategy to active specific and adoptive immunotherapy for cancer. Lay Summary: The proposed research is designed to develop a novel way to engage killer T cells and helper T cells (two important players in the immune system) to work in a collaborative and synergistic manner so as to orchestrate a robust and long-lived cellular immune attack against human cancers - a major cause of death. PUBLIC HEALTH RELEVANCE: "Cancer vaccines" and adoptive cell therapy for cancer have shown promising results but the two basic approaches need new strategies addressing two major impediments -- the lack of an effective way that would engage cognate CD4 T helper (Th) cells in the treatment and T regulatory (Treg) cell activities. We propose a novel strategy that could address both constraints through the employment of CD4 T cells engineered to express an MHC class I-restricted and tumor epitope specific T cell receptor (TCR) that are also used by cytolytic T cells (CTL) to recognize the tumor antigen. The TCR-engineered CD4 Th cells, therefore, could provide "help" towards the generation of a robust and long-lived CTL response as well as expand the therapeutic repertoire by mitigating Treg activities (as help and suppression are mutually opposed conditions) and through their own cytolytic potential.