Reversal of CMV-specific immune deficits in patients with glioblastoma

描述（由申请人提供）：包括我们在内的四个独立实验室最近发现并证实恶性胶质瘤通常与人巨细胞病毒抗原的表达相关，这为利用免疫系统的细胞溶解能力根除CMV感染的肿瘤细胞而不损害周围正常大脑提供了独特的机会。我们在使用CMV pp 65 RNA脉冲的树突状细胞（DC）增强CMV特异性免疫应答方面的努力已经证明了在患有新诊断的GBM的患者中增强CMV特异性细胞和体液应答并引发有希望的放射学和临床应答的能力。尽管有这些令人鼓舞的结果，我们发现GBM患者在诊断时引起严重的CMV特异性免疫缺陷，其特征在于在体外用CMV抗原刺激时不能产生有效的多功能T细胞应答（同时产生IL-2、IFN、TNF和细胞溶解颗粒（CD 107））。多功能T细胞应答已被证明介导对人类慢性病毒感染如HIV和CMV的有效控制，虽然DC疫苗接种提高了单功能CMV特异性T细胞的频率，但多功能应答并未增强。重要的是，我们已经发现，在体外使用pp 65 RNA脉冲的DC与添加外源性IL-2偶联或通过在刺激之前去除CD 4 + CD 25 + FOXP 3+调节性T细胞（TCFs），可以在这些相同的患者中恢复多功能CMV特异性T细胞应答。结果表明，逆转GBM患者体内细胞介导的缺陷可能是一个可行的目标，并可能显着提高抗肿瘤免疫治疗的疗效。在这个提议中，我们将探索使用CMV RNA脉冲的DC与编码细胞因子的RNA共转染来逆转GBM患者中细胞介导的缺陷的方法，所述细胞因子有利地调节多功能T细胞应答并抑制免疫抑制性T细胞的扩增。使用RNA修饰的DC可以允许免疫调节细胞因子的靶向递送，而不会诱导全身性Treg抑制的全身毒性或自身免疫风险。这些研究具有改善GBM患者临床结局的显著潜力。 公共卫生相关性：这项研究的意义在于，它可能会推进恶性脑肿瘤的新疗法，并提供可应用于许多其他癌症的治疗策略。改进的癌症治疗具有显著的潜力，可以改善受恶性疾病影响的患者的公共健康和生活质量。

DESCRIPTION (provided by applicant): The recent discovery and confirmation by four independent laboratories, including ours, that malignant gliomas are frequently associated with expression of human cytomegalovirus antigens provides a unique opportunity to harness the cytolytic power of the immune system to eradicate CMV-infected tumor cells without harming surrounding normal brain. Our efforts in enhancing CMV-specific immune responses using CMV pp65 RNA- pulsed dendritic cells (DCs) have demonstrated the capacity to enhance CMV-specific cellular and humoral responses and elicit promising radiographic and clinical responses in patients with newly-diagnosed GBM. Despite these encouraging results, we have found that patients with GBM elicit profound immunologic CMV- specific deficits at diagnosis that are characterized by the inability to mount effective polyfunctional T cell responses (simultaneous production of IL-2, IFN, TNF, and cytolytic granules (CD107)) upon stimulation with CMV antigens in vitro. Polyfunctional T cell responses have been shown to mediate the effective control of chronic viral infections such as HIV and CMV in humans, and while DC vaccination improved the frequency of monofunctional CMV-specific T cells, polyfunctional responses were not enhanced. Importantly, we have found that polyfunctional CMV-specific T cell responses could be restored in these same patients in vitro using pp65 RNA pulsed DCs coupled with addition of exogenous IL-2 or through the removal of CD4+CD25+FOXP3+ regulatory T cells (Tregs) prior to stimulation. The results suggest that reversal of cell-mediated deficits in vivo in patients with GBM may be a feasible goal and may significantly improve the efficacy of antitumor immunotherapy. In this proposal, we will explore methods to reverse cell-mediated deficits in patients with GBM using CMV RNA pulsed DCs co-transfected with RNAs encoding for cytokines that favorably modulate polyfunctional T cell responses and inhibit expansion of immunosuppressive Tregs. The use of RNA-modified DCs may allow for the targeted delivery of immunomodulatory cytokines without the induction of systemic toxicity or autoimmune risks of systemic Treg inhibition. These studies have significant potential to improve clinical outcomes for patients with GBM. PUBLIC HEALTH RELEVANCE: The significance of this research is that it may advance a new therapy for malignant brain tumors as well as provide a strategy for treatment that can be applied to many other cancers. Improved therapy for cancer has significant potential to improve public health and quality of life for patients affected by malignant disease.