Biologic Activity of Transferred HIV-specific CD8 Clones

描述（由申请人提供）：目前针对HIV-1感染的抗逆转录病毒治疗（ART）方案可以阻断病毒复制并提供实质性的临床益处，但长期治疗可能与显著的毒性相关，并且似乎无法根除病毒。增强受感染个体免疫系统的策略可能提供一种手段，以改善对抗逆转录病毒药物残留病毒复制的控制，并最终使减少对抗逆转录病毒药物的需求成为可能。如果能够确定达到预期抗病毒活性所需的反应的性质和程度，将有助于开发有效的基于免疫的疗法。我们的团队在人类病毒特异性CD8+ T细胞克隆的分离、体外扩增和过继转移方面拥有丰富的经验，作为建立强大的、功能性的CD8+ T细胞反应的策略，并通过修饰CD8+ T细胞来引入增强T细胞功能的基因，以及使用高灵敏度的分子技术来检测病毒储存库和HIV感染者PBMC、淋巴组织和粘膜组织中的持续HIV复制。我们的初步研究表明，在HIV感染者中，通过输注HIV特异性CD8+ T细胞克隆然后短暂的低剂量il - 2，可以在低病毒负荷的有效抗逆转录病毒治疗中实现非常高和持续的CD8+对HIV的应答。因此，我们建议确定是否为这些患者提供高频率的功能性分化CD8+效应细胞，特异于gag或在病毒生命周期早期表达的调节性病毒蛋白，可以有助于遏制正在进行的病毒复制和减少持久性病毒库。此外，与其他慢性病毒感染相比，HIV感染的一个标志是HIV特异性CD28+CD8+ T细胞的下降和CD28+CD8+ T细胞的积累。CD28共刺激分子表达的缺失（可能来自抗原驱动的分化）对CD8+ T细胞功能有显著影响，使细胞越来越依赖CD4+ T细胞的帮助。我们的初步研究表明，CD28可以在CD28+CD8+ T细胞中重新表达，并且这些细胞在识别特定靶标后重新获得产生IL2和增殖的能力。因此，我们建议对hiv特异性CD28+CD8+效应细胞进行基因修饰，并确定转移的CD28+CD8+ T细胞在可检测的血浆病毒血症个体中是否表现出更高的存活率、功能和抗病毒活性。

DESCRIPTION (provided by applicant): Current antiretroviral therapy (ART) regimens for HIV-1 infection can block viral replication and provide substantial clinical benefit, but long-term therapy can be associated with significant toxicities and does not appear capable of eradicating the virus. Strategies to boost the immune system of infected individuals might provide a means to improve control of residual viral replication on ART, and eventually make it possible to reduce the requirement for ART. Development of effective immune-based therapies would be facilitated if the nature and magnitude of responses required to achieve the desired antiviral[ activity could be defined. Our group has extensive experience with the isolation, in vitro expansion, and adoptive transfer of human virus-specific CD8+ T cell clones as a strategy for establishing strong, functional CD8+ T cell responses, and with modification of CD8+ T cells to introduce genes that enhance T cell function, as well as with highly sensitive molecular techniques to detect viral reservoirs and persistent HIV replication in PBMC, lymphoid tissue, and mucosal tissue of HIV-infected individuals on potent ART. Our preliminary studies suggest that very high and sustained CD8+ responses to HIV might be achievable in HIV-infected individuals on potent ART with low viral burdens by infusion of HIV-specific CD8+ T cell clones followed by a brief course of low dose IL2. Thus, we propose to determine if providing such patients with a high frequency of functional differentiated CD8+ effector cells, specific for either gag or regulatory viral proteins expressed early in the viral life cycle, can contribute to containment of ongoing viral replication and reduction in persistent viral reservoirs. Additionally, one hallmark of HIV infection in comparison to other chronic viral infections is the decline of HIV-specific CD28+CD8+ T cells and accumulation of CD28+CD8+ T cells. The loss of expression of the CD28 costimulatory molecule, presumably from antigen-driven differentiation, has significant consequences on CD8+ T cell function, rendering the cells increasingly dependent on CD4+ T cell help. Our preliminary studies demonstrate that CD28 can be re-expressed in CD28+CD8+ T cells, and that such cells reacquire the ability to produce IL2 and proliferate following specific target recognition. Thus, we propose to genetically modify HIV-specific CD28+CD8+ effector cells and determine if transferred CD28+CD8+ T cells exhibit improved survival, function, and antiviral activity in individuals with detectable plasma viremia.