Enhancing CD8 T Cell Function by Abrogating Inhibition by Regulatory Proteins

描述(申请人提供)：大量体外扩增的抗原特异性CDS T细胞过继免疫疗法有可能成为治疗癌症或病毒感染的一种新的安全方法，但疗效往往有限。其中一个障碍是供者T细胞在体内的存活和功能保留不足，这通常可以通过共转移CD4辅助T细胞或通过注射IL-2来替代CD4帮助来维持。然而，许多肿瘤的特异性辅助性CD4T细胞尚未被确定，CD4T细胞通常是有限的，在治疗HIV感染的过程中可能会带来额外的问题，而且长时间的大剂量IL-2补充可能是无效和有毒的。过继免疫治疗的另一个主要障碍可能是转移的T细胞无法被体内的病毒和肿瘤靶点有效激活。肿瘤特异性T细胞通常具有低亲和力的TCRs，肿瘤或感染靶点的抗原处理机制或辅助信号受损，对靶细胞的长时间识别可诱导T细胞耐受。因此，提高CDS T细胞产生IL-2和自分泌IL-2的能力，降低CDS T细胞激活的阈值，或阻止抗原特异性CDS T细胞耐受的诱导，应能显著提高过继免疫治疗策略的疗效。减少由细胞内调节蛋白介导的CDS T细胞的抑制信号是提高CDS T细胞亲和力和功能或维持自分泌IL-2增殖和存活的一种潜在方法。我们已经确定Cbl-b、SHP-1和SOCS-1是增强CDS T细胞亲和力和功能的潜在靶点。缺乏这些基因的小鼠的CDS T细胞会导致T细胞反应性增强，并产生不依赖共刺激的IL-2。该项目的主要目标是确定是否通过表达Cbl-b、SHP-1或SoCS-1来减少Cbl-b、SHP-1或SoCS-1对CDS T细胞激活信号的负调控，或者通过表达特定的siRNA来降低这些蛋白的内源性水平，是否可以改善T细胞的亲和力和功能，并使这些细胞在治疗慢性病毒感染或小鼠恶性肿瘤模型中更有效。此外，我们将在临床前研究中确定这些调节蛋白取消抑制是否可以增强人CDS T细胞的亲和力、增殖和存活率。 慢性病毒感染和癌症是主要的公共卫生问题。T细胞过继免疫治疗有可能成为治疗病毒感染和恶性肿瘤的一种有效和广泛应用的方法。然而，由于体内存活和功能的不足，转移的T细胞的疗效受到限制。这些研究将确定，在临床前研究中，通过基因修饰T细胞以改善功能和存活率是否可以增强慢性病毒感染或恶性肿瘤小鼠模型的过继免疫治疗方法，以及人类病毒和肿瘤特异性T细胞的存活和功能。

DESCRIPTION (provided by applicant): Adoptive immunotherapy with large numbers of in vitro expanded antigen-specific CDS T cells has the potential to become a novel and safe treatment modality for cancer or viral infections, but efficacy is often limited. One obstacle is insufficient in vivo survival and retention of function by donor T cells, which can often be sustained by cotransfer of CD4 helper T cells or by IL-2 administration to substitute for CD4 help. However, specific helper CD4 T cells have not been identified for many tumors, CD4 T cells are often limiting and can be pose additional problems during treatment of HIV infection, and prolonged high-dose IL-2 supplementation can be both inefficient and toxic. Another major obstacle to adoptive immunotherapy can be the failure of transferred T cells to be effectively activated by viral and tumor targets in vivo. T cells specific for tumors often have low affinity TCRs, malignant or infected targets can have impaired antigen processing machinery or accessory signals, and prolonged recognition of target cells can induce T cell tolerance. Thus, increasing the capacity of CDS T cells for IL-2 production and autocrine IL-2 mediated proliferation, reducing the threshold for CDS T cell activation, or preventing induction of tolerance in antigen-specific CDS T cells should significantly enhance the efficacy of adoptive immunotherapeutic strategies. One potential means to increase CDS T cell avidity and function or sustain autocrine IL-2 proliferation and survival is to reduce inhibitory signals in transferred CDS T cells mediated by intracellular regulatory proteins. We have identified Cbl-b, SHP-1, and SOCS-1 as potential targets to enhance CDS T cell aviditiy and function. CDS T cells from mice deficient in these genes results in increased T cell reactivity and costimulation independent IL-2 production. The major goals of this project are to determine if decreasing the negative regulation of activation signals in CDS T cells by Cbl-b, SHP-1, or SOCS-1 by expression of dominant negative versions of these proteins, or by reducing endogenous levels of these proteins via expression of specific siRNA, can improve T cell avidity and function and render these cells more effective in therapy of chronic viral infections or malignancy in mouse models. Additionally, we will determine if abrogating inhibition by these regulatory proteins can enhance the avidity, proliferation and survival of human CDS T cells in preclinical studies. Chronic viral infections and cancer represent major public health concerns. Adoptive immunotherapy with T cells has the potential to become an effective and broadly applicable approach for the treatment of viral infections and malignancy. However, the efficacy of transferred T cells is limited by insufficient in vivo survival and function. These studies will determine if genetically modifying T cells to improve function and survival can enhance adoptive immunotherapy approaches in mouse models of chronic viral infection or malignancy as well as the survival and function of human virus and tumor specific T cells in preclinical studies.