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）反应为中心的癌症的主动特异性和过继性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CD4+ T辅助细胞（Th）的参与。我们发现CD4+ T细胞——被设计表达MHC I类限制性黑色素瘤表位特异性T细胞受体（TCR），也被CTL用来识别表位——合成Th1型细胞因子，并以表位特异性的方式对黑色素瘤细胞和替代靶细胞表现出细胞溶解潜能。我们建议对这种MHC i类限制性TCR工程CD4 T细胞在抗黑色素瘤免疫反应中的生物学特性进行全面研究，重点关注它们作为效应细胞和辅助T细胞的作用。中心假设是“考虑到帮助和抑制是两个相互对立的条件，如果可以通过相同的TCR和相同的MHC限制分子使CTL和辅助细胞同时识别感兴趣的肿瘤相关表位，CD4+ T细胞将促进产生强大而持久的CTL反应并减轻Treg激活。”此外，通过展示其自身的抗肿瘤效应功能，它们将扩大抗肿瘤的功能范围。为了验证这一假设，我们将CD4+ T细胞设计成表达黑色素瘤表位（MART-127-35和Tyrosinase368-376）特异性TCR的几种特异性靶细胞，并在体外试验和HLA- A2.1/Kb转基因小鼠中使用由小鼠恒定区和人类可变区组成的嵌合人-小鼠TCR。CD4+ Th细胞的生物学特性将通过体外CTL生成实验、体外Treg激活实验和嵌合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HLA-A2.1/Kb小鼠中进行综合表型和功能表征来评估。所提出的研究将导致开发一种新的和补充策略，以主动特异性和过继性免疫治疗癌症。摘要：这项拟议的研究旨在开发一种新的方法，使杀伤T细胞和辅助T细胞（免疫系统中的两个重要角色）以协同和协同的方式工作，从而协调一种强大而持久的细胞免疫攻击，以对抗人类癌症-一种主要的死亡原因。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有希望的结果，但这两种基本方法需要新的策略来解决两个主要障碍——缺乏有效的方法来参与同源CD4 T辅助（Th）细胞的治疗和T调节（Treg）细胞的活动。我们提出了一种新的策略，可以通过使用CD4 T细胞来表达MHC i类限制性和肿瘤表位特异性T细胞受体（TCR）来解决这两种限制，TCR也被细胞溶解T细胞（CTL）用来识别肿瘤抗原。因此，tcr工程CD4 Th细胞可以提供“帮助”，以产生强大而持久的CTL反应，并通过减轻Treg活性（因为帮助和抑制是相互对立的条件）和通过其自身的细胞溶解潜力来扩大治疗范围。

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.