Biologic Activity of Transferred HIV-specific CD8 Clones

描述(申请人提供)：目前针对HIV-1感染的抗逆转录病毒疗法(ART)可以阻止病毒复制并提供实质性的临床益处，但长期治疗可能与重大毒性相关，似乎无法根除病毒。增强感染者免疫系统的策略可能提供一种手段，改善对ART上残留病毒复制的控制，并最终使降低对ART的需求成为可能。如果能够确定实现所需抗病毒[活性]所需的反应的性质和大小，将有助于开发有效的基于免疫的疗法。我们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，以此作为建立强大、功能强大的CD8+T细胞反应的策略，并通过修饰CD8+T细胞以引入增强T细胞功能的基因，以及在有效的抗逆转录病毒疗法中利用高灵敏的分子技术检测HIV感染者的PBMC、淋巴组织和粘膜组织中的病毒库和持续的HIV复制。我们的初步研究表明，在HIV感染者中，通过注射HIV特异性CD8+T细胞克隆，然后进行短暂的低剂量IL2治疗，可以在病毒负荷较低的有效ART疗法中实现非常高和持续的CD8+应答。因此，我们建议确定为这些患者提供高频率的功能分化的CD8+效应细胞，无论是针对GAG还是在病毒生命周期早期表达的调节性病毒蛋白，是否有助于遏制正在进行的病毒复制和减少持续病毒库中的病毒。此外，与其他慢性病毒感染相比，艾滋病毒感染的一个特征是HIV特异性CD28+CD8+T细胞的下降和CD28+CD8+T细胞的积累。CD28共刺激分子的表达缺失，可能是由于抗原诱导的分化，对CD8+T细胞的功能有重大影响，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，并且这种细胞在特定靶点识别后重新获得产生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细胞在可检测到血浆病毒血症的个体中是否表现出更好的存活率、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.