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类巨细胞病毒抗原的表达有关，这为利用免疫系统的细胞溶解能力根除巨细胞病毒感染的肿瘤细胞而不损害周围正常的大脑提供了一个独特的机会。我们利用CMV pp65 RNA脉冲树突状细胞（DCs）增强CMV特异性免疫反应的研究已经证明，它能够增强CMV特异性细胞和体液反应，并在新诊断的GBM患者中引发有希望的放射学和临床反应。尽管这些令人鼓舞的结果，我们发现GBM患者在诊断时引发了深刻的CMV特异性免疫缺陷，其特征是在体外CMV抗原刺激下无法建立有效的多功能T细胞反应（同时产生IL-2， IFN， TNF和细胞溶解颗粒（CD107））。多功能T细胞反应已被证明可以有效地介导人类慢性病毒感染，如HIV和CMV，虽然DC疫苗接种提高了单功能CMV特异性T细胞的频率，但多功能反应并未增强。重要的是，我们发现在体外使用pp65 RNA脉冲dc加上外源性IL-2或通过在刺激前去除CD4+CD25+FOXP3+调节性T细胞（Tregs），可以恢复这些患者的多功能cmv特异性T细胞反应。结果表明，在GBM患者体内逆转细胞介导的缺陷可能是一个可行的目标，并可能显著提高抗肿瘤免疫治疗的疗效。在本研究中，我们将探索利用CMV RNA脉冲dc与编码细胞因子的RNA共转染的方法来逆转GBM患者细胞介导的缺陷，这些细胞因子有利于调节多功能T细胞反应并抑制免疫抑制Tregs的扩增。使用rna修饰的dc可能允许免疫调节细胞因子的靶向递送，而不会诱导全身毒性或全身Treg抑制的自身免疫风险。这些研究对于改善GBM患者的临床结果具有重要的潜力。

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.