Anti-melanoma Activity of Combined Lymphopenia and Immunotherapy

尽管在癌症患者的外周血和骨髓中检测到肿瘤特异性T细胞，但这些 T细胞不能调节巨大肿瘤的完全消退。扩大免疫治疗途径 而激活这些T细胞很少会导致肿瘤的完全消退或治愈。在癌症患者中，许多因素 可能导致对肿瘤的无效免疫，包括调节性免疫细胞，如CD4*CD25* 调节性T细胞和GDI1b*Gr1*未成熟髓系细胞。在这些研究中，我们打算降低免疫力 介导性抑制和删除荷瘤小鼠无应答宿主抗肿瘤T细胞的治疗 全身照射(TBI)。我们打算通过过继的方式用“新的”T细胞重建免疫系统 幼稚T细胞的转移。我们将用多肽冲击的树突状细胞(DC)疫苗培养这些T细胞。 初步研究表明，这种策略会延缓肿瘤的生长，但不会提高患者的存活率 黑色素瘤荷瘤小鼠。为了改进这一模型，已知的两种免疫系统的重组和活性 抑制群体，CD4*CD25*Foxp3*T细胞和CD11b*Gr1*未成熟髓系细胞，将被检测。 通过消耗这些种群，我们将确定这些抑制细胞对 抗肿瘤免疫的研究进展。此外，导致抗肿瘤发展的战略 将探索记忆T细胞和长期免疫，包括过继转移肿瘤反应性T细胞。 树突状细胞(DC)是诱导有效抗肿瘤所必需的强大的抗原提呈细胞 初级和记忆性T细胞反应。我已经证明，将肿瘤靶向DC上的细胞表面受体 可增强抗肿瘤T细胞反应，并与细菌来源的药物联合治疗 免疫佐剂可以提高DC疫苗对肿瘤的免疫效果。我假设已经确立的回归 黑色素瘤将需要多种免疫治疗方法来诱导有效的抗肿瘤T细胞 活动。具体地说，我打算实施诱导强大的抗肿瘤T细胞反应的疗法 通过以下特定目的抗黑色素瘤：1.从实验上探讨其作用机制 淋巴细胞减少后诱导的免疫调节；2.检测DC疫苗在儿童中的免疫效果 通过转移富含CDS*记忆T细胞的T细胞来治疗淋巴细胞减少症；3.确定 树突状细胞疫苗和CpG辅助治疗联合放疗和过继T细胞 移植入小鼠黑色素瘤模型。本申请中概述的实验研究旨在 继续成功地开展临床前工作，以制定针对黑色素瘤的免疫战略。这些发现 可能会对人类临床免疫治疗试验产生重大影响。

Despite detection of tumor-specific T cells in the peripheral blood and bone marrow of cancer patients, these T cells are unable to mediate total regression of bulky tumors. Immunotherapeutic approaches to expand and activate these T cells rarely result in total tumor regressions or cures. In cancer patients, many factors may contribute to ineffective immunity against tumors including regulatory immune cells such as CD4*CD25* regulatory T cells and GDI 1b* Gr1* immature myeloid cells. In these studies, we intend to decrease immune mediated suppression and delete unresponsive host anti-tumor T cells in tumor bearing mice by treatment with total body irradiation (TBI). We intend to reconstitute the immune system with "new" T cells by adoptive transfer of naive T cells. We will educate these T cells with peptide-pulsed dendritic cell (DC) vaccination. Initial studies have shown that this strategy leads to a delay in tumor growth but does not enhance survival in melanoma bearing mice. In order to improve this model, the reconstitution and activity of \wo known immune inhibitory populations, CD4*CD25*foxp3* T cells and CD11b*Gr1* immature myeloid cells, will be examined. By depleting these populations, we will determine the effects, if any, these inhibitory cells have on the development of anti-tumor immunity. In addition, strategies that lead to the development of anti-tumor memory T cells and long-term immunity will be explored, including adoptive transfer of tumor reactive T cells. Dendritic cells (DC) are potent antigen presenting cells required for the induction of effective anti-tumor primary and memory T cell responses. I have shown that targeting tumors to cell-surface receptors on DC can lead to enhanced anti-tumor T cell responses and combination therapy with bacterial derived immunoadjuvants can improve DC vaccination against tumors. I hypothesize that regression of established melanoma will require multiple immunotherapeutic approaches for the induction of effective anti-tumor T cell activity. Specifically, I intend to implement therapies for the induction of potent anti-tumor T cell responses against melanoma through the following Specific Aims: 1. To investigate experimentally the mechanisms of immune regulation induced after lymphopenia; 2.To examine the efficacy of DC-based vaccination in the setting of lymphopenia by transfer of T cells enriched in CDS* memory T cells; 3. To determine the efficacy of dendritic cell vaccination and CpG adjuvant therapy in combination with irradiation and adoptive T cell transfer in a murine melanoma model. The experimental studies outlined in this application are designed to continue successful preclinical efforts to generate immunization strategies against melanoma. These finding could have significant translation to human clinical immunotherapeutic trials.