Local control of anti-tumor/anti-self reactivity in low-affinity ACT

 描述(由申请人提供)：在美国国家癌症研究所(NCI)和美国国家过敏和传染病研究所(NIAID)的大力支持下，针对肿瘤浸润性和受体工程T细胞的癌症和慢性病毒感染的过继细胞疗法(ACT)已经从实验环境进入了越来越多的临床现实。尽管高亲和力T细胞的转移对各种类型的肿瘤具有很大的前景，但它们的超生理亲和力和抗原敏感性可以对表达靶向抗原的自身组织造成显著的“靶向”免疫病理损伤。扩大ACT可治疗肿瘤的疗效和范围的一个关键目标是设计出有利于前者的控制抗肿瘤和抗自身免疫之间的平衡的方法。这个探索性项目的目标是确定是否可以通过免疫操作肿瘤微环境来诱导表达中等亲和力受体的CD8+T细胞特异性地根除肿瘤，而不会在没有这种变化的情况下对健康的自身组织造成自身免疫损伤。这项工作将在卵巢癌的小鼠模型(ID8)中进行，该模型的特征是在RIP-Mova小鼠中与胰腺和肾脏共享模型抗原的表达。在ID8荷瘤RIP-Mova小鼠中，将使用对共同抗原具有中等亲和力的OT-3 CD8+T细胞进行ACT，这种T细胞反映了人类的耐受后谱系，因为它们已经经历了阴性选择，并保持对其同源外周抗原的无知，除非它们被特别准备这样做。目的在对肿瘤和自身反应性阈值密切相关的假设下，我将确定肿瘤控制与中等亲和力CD8+T细胞靶向自身免疫的治疗参数。这些实验将检验细胞数量和启动刺激在诱导肿瘤控制与自身免疫破坏胰岛方面的作用。目的II将评估肿瘤微环境的改变是否能使一些低于自身免疫阈值的OT-3细胞选择性地识别已治疗的肿瘤和远端肿瘤，其工作假设是局部免疫调节可以通过中等亲和力的T细胞为肿瘤控制打开一扇机会之窗。在这方面要测试的修改包括：A)去除抑制性细胞类型(调节性T细胞、2型巨噬细胞、髓系来源的抑制细胞)或信号(转化生长因子-β、IL-6、IL-10、PD-1/L1和CTLA-4)；B)通过瘤内免疫刺激细胞因子(IL-2、IL-12)或共刺激信号(CD27、4-1BB、CD40)增强OT-3的局部激活；以及C)通过瘤内注射CXCR3趋化因子(CXCL9/10)增加OT-3细胞的局部归巢和滞留。如果成功，该项目将支持一种新的范式，使更多的肿瘤特异性TCR能够用于ACT，并将极大地减少靶向毒性的发生，这些毒性限制了它在更广泛的肿瘤类型中的应用。

 DESCRIPTION (provided by applicant): Based significantly on the efforts of both intramural and extramural research supported by the National Cancer Institute (NCI) and the National Institutes of Allergy and Infectious Disease (NIAID), adoptive cellular therapy (ACT) of cancer and chronic viral infections with tumor-infiltrating and receptor-engineered T cells has moved from experimental setting to one of increasing clinical reality. Although transfer of high-affinityT cells holds great promise for a variety of tumor types, their supraphysiologic affinities and antigen sensitivity can cause significant "on-target" immunpathologic damage to self-tissues that share expression of the targeted antigen. A key goal for expanding the efficacy and range of tumors treatable by ACT would be realized by devising ways of controlling the balance between anti-tumor and anti-self-immunity to favor the former. The goal of this exploratory project is to determine whether CD8+ T cells expressing moderate-affinity receptors can be induced to specifically eradicate tumors through immunologic manipulation of their tumor microenvironment without autoimmune damage to healthy self-tissues where such alterations are absent. This work will be carried out in a murine model of ovarian carcinoma (ID8) which features shared expression of a model antigen with both pancreas and kidney in RIP-mOVA mice. ACT will be performed in ID8 tumor-bearing RIP-mOVA mice using moderate affinity OT-3 CD8+ T cells specific for the shared antigen that mirror the post-tolerant repertoire in humans in that they have undergone negative selection and remain ignorant of their cognate peripheral antigen unless they are specifically primed to do so. Aim I will define the therapeutic parameters of tumor control versus on-target autoimmunity by moderate-affinity CD8+ T cells, with the working hypothesis that the threshold for reactivity to both tumor and self is closely coupled. These experiments will examine the role of cell number and priming stimulus in inducing tumor control versus autoimmune destruction of beta islets. Aim II will evaluate whether alterations of tumor microenvironment can allow a number OT-3 cells that is below the threshold for autoimmunity to selectively recognize treated and distal tumors, with the working hypothesis that local immunomodulation can open a window of opportunity for tumor control by moderate affinity T cells. Modifications to be tested in this regard include A) removing inhibitory cell types (regulatory T cells, type 2 macrophages, myeloid-derived suppressor cells) or signals (TGF-β, IL-6, IL-10, PD-1/L1, and CTLA-4), B) enhancing local OT-3 activation with intratumoral immunostimulatory cytokines (IL-2, IL-12) or costimulatory signals (CD27, 4-1BB, CD40), and C) increasing local homing and retention of OT-3 cells by intratumoral injection of CXCR3 chemokines (CXCL9/10). If successful, this project will support a new paradigm that will enable a greatly expanded repertoire of tumor-specific TCRs to be used in ACT, and will greatly decrease the occurrence of on-target toxicities that have limited its application to a broader range of tumor types.