Purging the latent HIV reservoir at ART inititation: A new eradication strategy

 产品说明：现在很清楚，单靠抗逆转录病毒疗法（ART）并不能根除艾滋病毒：即使经过15年以上的强化和持续治疗，除了例外情况外，在停止ART后的几周内，病毒的传播仍会恢复。一小部分潜伏感染的细胞，通常被称为HIV感染的“储存库”，为反弹性病毒血症提供了长期来源。诱导HIV表达与ART相结合已被提出作为消除持续感染细胞的策略，其最终可能导致病毒根除。然而，目前的方法都没有导致潜伏库大小的显著减少。对这些令人失望的结果的一个可能的解释是缺乏有效的HIV特异性CD 8 T细胞来消除病毒抑制受试者中最近重新激活的潜伏感染的CD 4 T细胞。事实上，伴随着病毒抗原载量的减少，HIV特异性CD 8 T细胞在ART开始后迅速消失，并且在抑制治疗期间几乎检测不到。因此，在长期接受抗逆转录病毒治疗的个体中实施的休克和杀死策略可能会失败。一种根本不同的方法是，当HIV特异性CD 8 T细胞仍然处于高频率时，开始ART时重新激活预先存在的潜伏性储存库。我们假设，在ART启动期间存在一个机会窗口，其中使用再活化剂将重新活化潜伏感染的CD 4 T细胞（休克），并导致HIV特异性CD 8 T细胞（杀伤）对HIV储库的杀伤增强，因为这些细胞在此阶段仍以高频率存在。这项提案的主要目的是提供一个证据， 在SIV模型中的概念是，在ART开始时施用的再活化剂的添加将导致潜伏病毒库的大小的显著减小，这是由于CD 8 T细胞的点杀伤。为了实现这一目标，我们将使用苔藓抑素-1（BRYO-1）作为基准再活化剂，因为我们已经观察到这种PKC激动剂是重新激活来自病毒抑制个体的人CD 4 T细胞中潜伏HIV的最有效分子。在R21阶段，我们将验证BRYO-1可用作SIV模型中的基准再活化剂，并确定体内使用的最佳剂量。在R33阶段，我们将在非人灵长类动物（NHP）HIV模型中测试这一新概念，SIV感染印度恒河猴，特别选择表达MHC 1类等位基因Mamu-A*01，该等位基因与有效的SIV特异性CD 8 T细胞应答相关。我们将比较将接受单独ART、ART +延迟BRYO-1和ART +立即BRYO-1的动物中潜伏储库的大小，并证明在ART起始时接受BRYO- 1的动物中潜伏储库的消除是由CD 8 T细胞杀伤介导的。此外，我们将在这些动物中中断ART，以确定这种旨在实现功能性治愈的新策略的潜在临床益处。这项研究将为根除剂与ART联合给药的临床试验的快速发展铺平道路。

 DESCRIPTION: It is now clear that antiretroviral therapy (ART) alone does not eradicate HIV: Even after more than 15 years of intensive and continuous therapy, the spread of the virus resumes within a few weeks upon cessation of ART in all but exceptional cases. A small pool of latently infected cells, usually referred as the "reservoir" of HIV infection, provides a long-live source of rebound viremia. Inducing HIV expression combined with ART has been proposed as a strategy to eliminate persistently infected cells that could ultimately lead to viral eradication However, none of the current approaches has led to a significant decrease in the size of the latent reservoir. A likely explanation for these disappointing results is given by the lack of potet HIV specific CD8 T cells to eliminate the recently reactivated latently infected CD4 T cells in virally suppressed subjects. Indeed, concomitant to the decrease in viral antigen load, HIV-specific CD8 T cells rapidly vanish after ART initiation and remain barely detectable during suppressive therapy. Therefore, shock and kill strategies implemented in individuals on long-term ART are likely to fail. A fundamentally different approach is to reactivate the pre-existing latent reservoir when ART is started while HIV-specific CD8 T cells are still at high frequencies. We hypothesize that there is a window of opportunity during ART initiation where the use of a reactivating agent would reactivate latently-infected CD4 T cells (shock) and lead to an enhanced killing of the HIV reservoir by HIV-specific CD8 T cells (kill), as these cells are still present at high frequency at this stage. The major objective of this proposal is to provide a proof of concept in the SIV model that the addition of a reactivating agent administered at ART initiation will lead to a significant decrease in the size of the latent viral reservoir due to potnt killing by CD8 T cells. To achieve this objective, we will use bryostatin-1 (BRYO-1) as a benchmark reactivating agent since we have observed that this PKC agonist is the most potent molecule to reactivate latent HIV in human CD4 T cells from virally suppressed individuals. In the R21 phase, we will validate that BRYO-1 can be used as benchmark reactivating agent in the SIV model and determine the optimal dose to be used in vivo. During the R33 phase, we will test this new concept in the non-human primate (NHP) model of HIV, SIV infection of Indian origin rhesus macaques specifically selected for expressing the MHC class 1 allele Mamu-A*01, that has been associated with potent SIV-specific CD8 T cell responses. We will compare the size of the latent reservoir in animals that will receive ART alone, ART + delayed BRYO-1 and ART + immediate BRYO-1 and demonstrate that the elimination of latent reservoir in animals receiving BRYO- 1 at ART initiation is mediated by CD8 T cell killing. In addition, we will interrupt ART in these animals to determine the potential clinical benefit of this novel strategy aimed at achieving a functional cure. This study will pave the way to the rapid development of clinical trials in which an eradication agent will be administered together with ART.