Amplifying and Redirecting CMV-specific CD8 T cells to provide sustained control of HIV infection

HIV感染者的免疫系统在重新激活后无法消除潜伏感染的细胞， 导致停用抗逆转录病毒治疗后病毒血症复发，妨碍功能治愈。这 对艾滋病毒携带者(PWH)来说，终身抗逆转录病毒治疗是必要的。需要新的策略来动员免疫系统 以防止艾滋病病毒在ART停止后从艾滋病毒储存库中出现。我们最近开发了SynTacs， 由连接MHC分子和MHC分子的二聚体Fc结构域支架组成的不可熔免疫刺激生物制品 能够传递抗原特异性TCR信号的病毒衍生多肽(c-pMHC)和提供 明确的共刺激信号。我们证明了携带CMV衍生多肽和抗CD28的SynTacs ScFv或4-1BBL信号模块，刺激旺盛和选择性的体外和体内高度扩张 PWH PBMC中的多功能CMV特异性CD8T细胞在体内表现出较强的抗CMV活性。我们 最近还描述了CAR-T细胞在体外和体内的有效抗HIV活性，这种细胞使用一种新的两种- 分子双CAR结构共同表达两个独立的CAR，每个识别一个不同的gp120表位。 HIV特异性T细胞反应或CAR-T细胞治疗未能提供对HIV感染的持续控制，因为 即使在没有突变免疫的情况下，它们的功能性抗艾滋病毒活性最终也会减少或丧失 逃走。相比之下，CMV特异性T细胞反应由效应器记忆CD8T细胞组成，CD8T细胞维持其 细胞因子释放、杀伤和增殖的能力，实际上随着时间的推移而扩大，这种表型被描述为 内存膨胀。我们假设，结合SynTacs激活并显著扩展CMV- 通过新的策略将特定的CD8 T细胞重新定向到消除HIV感染的细胞，将利用高度的 功能性和恢复力强的CMV特异性CD8 T细胞反应，提供更好的艾滋病毒感染免疫控制。 我们建议结合SynTacs的能力来选择性地激活并显著扩展CMV特异性CD8 具有强大和持续的抗病毒活性的T细胞具有三个特定的目的(SA)，以将它们重定向到针对HIV- 被感染的细胞。我们要么将扩增的CMV CD8 T细胞转化为HIV特异性CAR T细胞(SA 1)，要么 抗HIV T细胞(SA 2)，或修改synTac结构以连接CMV-c-pMHC、gp120-结合子和共刺激分子 配体，以充分激活并引导CMV CD8 T细胞靶向HIV感染细胞(SA 3)，从而动员 体内免疫反应，控制艾滋病毒感染，消除重新激活的潜伏感染细胞，并提供 持续无抗逆转录病毒药物治疗缓解威斯康星医院的艾滋病毒感染。此外，我们还将利用synTacs提供 定义了共刺激信号，以扩展我们关于不同共刺激信号容量的知识 产生最强大的CD8T细胞和CAR-T细胞，以消除再次激活的潜伏感染的T细胞。

The immune system of HIV-infected individuals is unable to eliminate latently infected cells following reactivation, resulting in the recurrence of viremia after stopping antiretroviral therapy, preventing functional cure. This necessitates lifelong ART for people with HIV (PWH). New strategies are needed to mobilize the immune system to prevent the emergence of HIV from the HIV reservoir after ART cessation. We recently developed synTacs, infusible immunostimulatory biologics consisting of dimeric Fc-domain scaffolds linking MHC molecules and virus-derived peptides (c-pMHC) capable of delivering antigen-specific TCR-signals and ligands that supply defined costimulatory signals. We demonstrated that synTacs bearing CMV-derived peptides, and anti-CD28 scFv or 4-1BBL signaling modules, stimulated vigorous and selective ex vivo and in vivo expansion of highly polyfunctional CMV-specific CD8+ T cells in PWH PBMC, which displayed potent in vivo anti-CMV activities. We also recently described the potent in vitro and in vivo anti-HIV activity of CAR-T cells that use a novel two- molecule duoCAR architecture to co-express two independent CARs, each recognizing a distinct gp120 epitope. HIV-specific T cell responses or CAR-T cell treatments fail to provide sustained control of HIV infection because of the eventual reduction or loss of their functional anti-HIV activity, even in the absence of mutational immune escape. In contrast, CMV-specific T cell responses consist of effector memory CD8 T cells that maintain their capacity for cytokine release, killing and proliferation and actually expand over time, a phenotype described as memory inflation. We hypothesize that combining the capacity of synTacs to activate and markedly expand CMV- specific CD8 T cells with novel strategies to redirect them to eliminate HIV-infected cells, would exploit the highly functional and resilient CMV-specific CD8 T cell responses to provide improved immune control of HIV infection. We propose to combine the capacity of synTacs to selectively activate and markedly expand CMV-specific CD8 T cells with potent and sustained anti-viral activity with three Specific Aims (SA) to redirect them to target HIV- infected cells. We will either convert the expanded CMV CD8 T cells into HIV-specific CAR T cells (SA 1), or anti-HIV T cells (SA 2), or modify the synTac structure to link CMV-c-pMHC, gp120-binders and costimulatory ligands, to both fully activate and direct CMV CD8 T cells to target HIV-infected cells (SA 3), thereby mobilizing an in vivo immune response that controls HIV infection, eliminates reactivated latently infected cells and provides sustained ART-free remission of HIV infection to PWH. Furthermore, we will also utilize synTacs delivering defined costimulatory signals, to extend our knowledge regarding the capacity of different costimulatory signals to generate the most potent CD8+ T cells and CAR-T cells for eliminating reactivated latently infected T cells.