Engineering High-Affinity T Cell Receptors Against Cancer Antigens

描述(由申请人提供)：T细胞具有强大的能力来调查和摧毁已被感染或转化的细胞。T细胞表达T细胞受体(TCR)，它能识别与细胞表面主要组织相容性复合体(MHC)分子结合的短肽片段。各种研究表明，T细胞(肿瘤浸润性淋巴细胞，TIL)在患者肿瘤中的较大渗透与预后的改善相关。如果TCR识别的多肽/MHC具有足够的亲和力，T细胞就会被激活，并释放颗粒酶和穿孔素来摧毁宿主细胞。尽管正常的免疫系统有可能检测并摧毁转化的细胞，但已确定的癌症显然避免了这种免疫介导的识别和破坏。免疫治疗的一个首要目标是促进TCR对癌症多肽MHC复合体的识别，以便利用人体自身的免疫系统来破坏转化的组织。在肿瘤发生过程中，细胞通过MHC分子表达突变和异常过表达的蛋白质。实现T细胞对癌症组织识别的一种机制是设计高亲和力的TCR与这些癌症多肽MHC复合体结合。目前已鉴定出300多个与不同类型的癌症组织相关的PepMHC复合体，但很少有针对这些PepMHC复合体的高亲和力TCR被分离出来。该项目的目标是设计针对几种癌症多肽MHC复合体的高亲和力TCR，并在采用的癌症T细胞模型中测试它们促进肿瘤消退的能力。此外，该项目还试图开发一种更有效的方法来分离高亲和力的TCR。我的具体目标是：目标1：利用定向进化和亲和力成熟的方法开发针对Survivin/HLA-A2的高亲和力TCR。目前，我们已经分离出抗癌抗原Mart1和WT1的高亲和力TCRs。开发一种针对Survivin的高亲和力受体将增加在其他AIMS测试的受体的曲目。AM 2：测试嵌合抗原受体(CAR)形式的高亲和力TCR，它将在体内介导针对Mart1、WT1和Survivin抗原的T细胞活性。这一目标将使人们更好地了解高亲和力TCR如何在体内使用，从而使未来的临床开发成为可能。目的：建立一种通用支架快速分离高亲和力TCRs的方法。目前分离高亲和力TCR的技术是耗时的，包括分离T细胞克隆，然后逐个操作TCR基因。这一目标将开发一个最佳的支架文库，以便能够实现高亲和力TCR的快速分离，从而促进它们在各种癌症和更多患者的过继T细胞免疫疗法中的使用。

DESCRIPTION (provided by applicant): T cells have the powerful capability to survey and destroy cells that have become infected or transformed. T cells express T cell receptors (TCRs), which specifically recognize short peptide fragments bound to major histocompatibility complex (MHC) molecules on the cell surface. Various studies have shown that greater infiltration of T cells (tumor infiltrating lymphocytes, TILs) in a patient's tumor correlates with improved prognosis. If a peptide/MHC is recognized with sufficient affinity by the TCR, the T cell is activated and releases granzymes and perforins that destroy the host-cell. Despite potential for the normal immune system to survey and destroy transformed cells, established cancers have clearly avoided such immune-mediated recognition and destruction. An overarching goal of immunotherapy is to promote TCR recognition of cancer pepMHC complexes so that the body's own immune system can be harnessed to destroy transformed tissues. During oncogenesis, cells express mutated and aberrantly overexpressed proteins via MHC molecules. One mechanism to achieve T cell recognition of cancerous tissue is to engineer high-affinity TCRs to bind to these cancer pepMHC complexes. Over 300 pepMHC complexes associated with different types of cancerous tissue have been identified, yet very few high-affinity TCRs specific for these pepMHC complexes have been isolated. The goal of this project is to engineer high-affinity TCRs against several cancer pepMHC complexes and test their ability to promote tumor regression in adoptive T cell models of cancer. Also, this project seeks to develop a more efficient method for isolating high-affinity TCRs. My specific aims are: Aim 1: To develop a high-affinity TCR against survivin/HLA-A2 using directed evolution and affinity maturation. Currently, we have isolated high-affinity TCRs against the cancer antigens Mart1 and WT1. Developing a high-affinity receptor against survivin will add to repertoire to receptors tested in other aims. Am 2: To test high-affinity TCRs in a chimeric antigen receptor (CAR) format that will mediate T cell activity against Mart1, WT1 and Survivin antigens in vivo. This aim will allow a better understanding of how high-affinity TCRs can be used in vivo, so that future clinical development is possible. Aim 3: To develop a method for rapid isolation of high-affinity TCRs using a universal scaffold. Current techniques for isolating high-affinity TCRs are time-consuming, involving isolation of T cell clones followed by one-by-one manipulation of the TCR genes. This aim will develop an optimal scaffold library so that rapid isolation of high-affinity TCRs can be achieved, facilitating their use in adoptive T cell immunotherapies for diverse cancers and many more patients.