Unraveling the Mechanisms of HIV Persistence and Rebound

项目摘要/摘要（总体） 尽管 cART 长期抑制病毒血症，但 HIV 感染的持续存在构成了主要障碍 来治愈艾滋病毒。不幸的是，即使对于在急性感染期间开始接受 cART 的患者也是如此。因此，长期 持久性艾滋病毒储存库在感染后迅速传播，这一点在非人类灵长类动物中得到了证实 (NHP) HIV 模型。此外，来自几个小组和我们的数据强烈表明，残留的病毒复制 尽管 cART 完全抑制了病毒血症，但在组织中病毒血症仍在持续。我们正在进行的研究调查了 cART 中断后 NHP 模型中病毒反弹的“日食期”。这个“日食阶段”是关键 了解反弹过程，因为病毒在病毒血症之前就在组织中传播，并且受到以下因素的影响 适应性和先天反应以及宿主微环境。在我们早期（4天后）的研究中 感染）cART 启动，我们创新的 SIV-env 免疫PET-CT 引导分析和采样导致了一些 重要的、有时是意想不到的发现：1) 我们检测到 SIV 在整个宿主中扩张超过 1 周 cART 启动后，此后信号减弱； 2) 即使在 cART 6-8 个月后，免疫 PET/CT 仍 尽管血液中检测不到病毒血症，但仍具有足够的灵敏度来检测组织中残留的病毒（蛋白质）信号； 3) ART 中断后，病毒信号最早在 cART 中断 (ATI) 后 4 天反弹，而且 2 血浆中检测到病毒前几周； 4) 通过我们的 PET-CT 对反弹时收集的组织进行分析 引导尸检工作流程令人惊讶地表明，大多数感染细胞是骨髓细胞。之后 广泛的分析表明，这些细胞是肥大细胞（MC），一种主要存在于组织中的粒细胞， 我们证明表达CD4和CCR5。通过与当地 MC 专家合作，我们能够证明 原代组织 MC 在体外易受 HIV 感染，其易感性和支持病毒的能力 复制很大程度上受环境刺激的影响。在此 PPG 中，我们将利用几个重要的见解 以及我们当前 PPG 期间开发的创新技术，以研究 MC 有助于的假设 cART 期间组织中的 HIV 持续存在和/或导致 cART 中断后病毒反弹。此外，我们 将通过使用组织和组织对组织中的病毒种群进行系统解剖学分析来阐明病毒-宿主动态 通过我们创新的 PET-CT 引导采样工作流程分离细胞。这些组织也将被识别 通过分析我们目前已经认识到的“回弹组织”的其他特征 研究。该 PPG 由 3 个独立但高度互连的项目组成，1 个 NHP 科学核心 和 1 个行政核心。这 3 个项目都将以不同的方式使用来自 NHP 研究的组织以及 每个项目都有独特的资源，将解决不同但互补的问题，并最终解决 目标是剖析艾滋病毒持续存在和反弹的机制。

PROJECT SUMMARY/ABSTRACT (Overall) The persistence of HIV infection despite long term suppression of viremia by cART constitutes the major obstacle to HIV cure. This is unfortunately true even for patients initiated on cART during acute infection. Thus, long-term persistent HIV reservoirs are seeded rapidly post infection, and this was confirmed in the nonhuman primate (NHP) model of HIV. In addition, data from several groups and ours strongly suggest that residual viral replication is ongoing despite in tissues despite full suppression of viremia by cART. Our on-going studies investigate the “eclipse phase” of viral rebound in the NHP model after cART interruption. This “eclipse phase” is key to understand the rebound process since the virus is spreading in tissues before viremia and it is influenced by adaptive and innate responses as well as the host microenvironment. In our studies of early (4 days post- infection) cART initiation, our innovative SIV-env ImmunoPET-CT guided analysis and sampling led to several important, sometimes unexpected findings: 1) we detected SIV expansion throughout the entire host for >1 week post cART initiation, with signal decreasing thereafter; 2) Even after 6-8 months of cART, immunoPET/CT was sensitive enough to detect residual viral (protein) signal in tissues in spite of undetectable viremia in the blood; 3) upon ART interruption, viral signals rebounded as early as 4 days post cART interruption (ATI) but also 2 weeks before detection of virus in plasma; 4) analysis of the tissues collected at rebound through our PET-CT guided necropsy workflow surprisingly showed that the majority of infected cells were of myeloid cells. After extensive analysis, these cells revealed to be mast cells (MC), a predominantly tissue resident granulocytes that we demonstrate expresses CD4 and CCR5. By teaming up with a local MC expert, we were able to demonstrate that primary tissue MC are susceptible to HIV infection in vitro and their susceptibility and ability to support viral replication is heavily influenced by environmental stimuli. In this PPG, we will leverage several important insights and innovative techniques developed during our current PPG to investigate the hypothesis that MC contribute to HIV persistence in tissues during cART and/or contribute to viral rebound upon cART interruption. Moreover, we will clarify virus-host dynamics through phyloanatomical analysis of viral populations in tissues using tissues and cells isolated through our innovative PET-CT guided sampling workflow. These tissues will be identified also through the analysis of additional features of “rebound tissues” that we have recognized through our current studies. This PPG comprises of 3 independent, although highly interconnected projects, 1 scientific NHP core and 1 administrative core. The 3 projects will all use in different ways tissues from the NHP studies as well as resources unique to each project and will address different although complementary questions with the ultimate goal to dissect the mechanisms of HIV persistence and rebound.