TCR Engineered CD4 Cells as Helpers in Tumor Immunity

描述（由申请人提供）：以细胞溶解性T淋巴细胞（CTL）应答为中心的癌症主动特异性和过继免疫疗法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CD 4 + T辅助（Th）细胞的参与。我们已经发现，CD 4 + T细胞--被工程化以表达MHC I类限制性黑素瘤表位特异性T细胞受体（TCR），其也被CTL用于识别表位--合成Th 1型细胞因子，并以表位特异性方式表现出针对黑素瘤细胞和替代靶细胞的细胞溶解潜力。我们提出了一个全面的研究，这种MHC I类限制性TCR工程化的CD 4 T细胞的生物学在抗黑色素瘤的免疫反应，专注于其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限制性分子同时使CTL和辅助细胞识别肿瘤相关的感兴趣表位，则CD 4 + T细胞将促进产生稳健和持久的CTL应答并减轻Treg活化。此外，通过表现出自身的抗肿瘤效应子功能，它们将扩大抗肿瘤库。我们建议通过几个特定的目的来测试这一假设，这些目的设计有CD 4 + T细胞，这些T细胞被工程化以在体外测定中表达黑素瘤表位（MART-127-35和酪氨酸酶368 -376）特异性TCR，并且在体内使用由小鼠恒定区和人可变区组成的嵌合人-小鼠TCR在HLA-A2. 1/Kb转基因小鼠中表达。将通过体外CTL生成测定、体外Treg活化测定和嵌合TCR工程化T细胞过继转移至携带A2.1/KB转基因B-16黑素瘤细胞的HLA-A2.1/KB小鼠中的综合表型和功能表征来评估CD 4 + Th细胞的生物学。这项研究将为癌症的主动特异性和过继性免疫治疗提供一种新的补充策略。概述：这项研究旨在开发一种新的方法，使杀伤性T细胞和辅助性T细胞（免疫系统中的两个重要参与者）以协作和协同的方式工作，从而协调针对人类癌症的强大而持久的细胞免疫攻击-这是死亡的主要原因。 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-缺乏有效的方法来使同源CD 4辅助性T细胞（Th）参与治疗和T调节细胞（Treg）活动。我们提出了一种新的策略，可以解决这两个限制，通过就业的CD 4 T细胞工程表达的MHC I类限制性和肿瘤表位特异性T细胞受体（TCR），也用于细胞溶解性T细胞（CTL）识别肿瘤抗原。因此，TCR工程化的CD 4 Th细胞可以提供“帮助”以产生稳健和长寿命的CTL应答，以及通过减轻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展治疗库。

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.