Pathogenesis of Rebound SIV/HIV Viremia after Antiretrovral Therapy

项目摘要 该计划项目将增加对SIV/HIV病毒血症长期反弹的发病机制的了解 在“最好的情况”下实现艾滋病毒感染持续缓解的创新治疗策略的目标 场景。这种情况包括在感染后立即开始抗逆转录病毒治疗(“早期抗逆转录病毒疗法”)和 在规定的持续时间后停止治疗--同时短期使用一种新的辅助治疗策略 显著增加停止早期抗逆转录病毒治疗后持续缓解的受试者比例。这项建议 将定义SIV/HIV感染后早期持续感染的粘膜和其他组织中的细胞； 表征T细胞激活触发的机制，假设两者在早期启动病毒产生 ART的停止以及引起靶细胞易感性和病毒感染性的级联反应，从而导致病毒血症 反弹；并开始测试机制知情的、基于细胞的干预措施，以中断这些“恶性循环”。 旨在解决以下3个关于停止早期ART后反弹的假设。1.持久性病毒 在感染后不久，粘膜细胞内就会建立蓄水池，并引发病毒血症反弹。我们将确定 SIV最初在结肠和女性生殖道粘膜中建立潜伏期的细胞类型/亚型 在猕猴粘膜感染后的头几天，确定这些“病毒库”细胞是否仍留在 体内抑制ART过程中的粘膜；在细胞/组织模型中研究ART外这些细胞的病毒产生 体外、人源化的变态小鼠和体内的猕猴；并设计/执行一项初步的观察研究 人类。2.暂时抑制雷帕霉素的机制靶点(MTOR)会降低两种病毒的产量 从细胞储存库和新目标细胞对感染的易感性。我们将描述细胞的特征 MTOR活性下游的机制，启动从存储细胞产生病毒，并增加 靶细胞对感染的敏感性，通过T细胞受体(TCR)激活，髓系微生物产物激活 细胞，以及髓系细胞衍生细胞因子激活T细胞。将研究催化mTOR抑制剂的作用 在猕猴体内，建立了潜伏期/再激活的体外细胞模型，以及使用 结肠粘膜活检、切除的扁桃体组织和人源化的Drag小鼠。3.暂时增加病毒粒子 APOBEC3G(A3G)将降低病毒的传染性。在体外模型和人源化小鼠中，我们将测试 假设T细胞库在Vif表达前具有较低的A3G水平； 助推器“)将增加由它们产生的Vif阳性病毒粒子中的A3G水平；这促进了A3G介导的 病毒传播减少将增加mTOR抑制作用，以降低未感染的靶T细胞对 感染反弹；mTOR抑制将增强A3G对病毒粒子A3G含量的促进作用。

Project Summary This program project will add to understanding the pathogenesis of SIV/HIV viremia rebound with the long-term goal of innovating therapeutic strategies enabling sustained remission of HIV infection in a “best-case” scenario. This scenario involves initiating antiretroviral therapy (ART) soon after infection (“early ART”) and stopping it after a defined duration - along with short-term use of a new, adjunctive treatment strategy that will markedly increase the proportion of subjects with sustained remission after stopping early ART. This proposal will define the cells in mucosal and other tissues that SIV/HIV persistently infects early after infection; characterize T cell activation-triggered mechanisms hypothesized to both initiate virus production after early ART stops as well as to cause a cascade of target cell susceptibility and virus infectivity that leads to viremia rebound; and begin testing mechanism-informed, cell-based interventions to interrupt these “vicious cycles.” Aims address the following 3 hypotheses about rebound after stopping early ART. 1. Persistent virus reservoirs are established in mucosal cells soon after infection, and initiate viremia rebound. We will identify the cell types/subtypes in which SIV initially establishes latency in colon and female reproductive tract mucosa in the first days after mucosal infection of macaques; determine if those “virus reservoir” cells remain in the mucosa during suppressive ART in vivo; study virus production from those cells off-ART in cell / tissue models ex vivo, humanized DRAG mice, and macaques in vivo; and design/perform a pilot observational study of humans. 2. Temporarily inhibiting mechanistic target of rapamycin (mTOR) will decrease both virus production from cellular reservoirs and susceptibility of new target cells to infection. We will characterize cellular mechanisms downstream of mTOR activity that initiate virus production from reservoir cells, and increase target cell susceptibility to infection, via T cell receptor (TCR) activation, microbial product activation of myeloid cells, and T cell activation by myeloid cell-derived cytokines. Effects of catalytic mTOR inhibitors will be studied in macaques in vivo, established ex vivo cellular models of latency/reactivation, as well as new models using colon mucosal biopsies, excised tonsil tissue, and humanized DRAG mice. 3. Temporarily increasing virion APOBEC3G (A3G) will decrease virus infectivity. In the ex vivo models and humanized mice, we will test the hypotheses that T cell reservoirs have low A3G levels before Vif is expressed; that tool compounds (”A3G- boosters”) will increase A3G levels in Vif-positive virions produced from them; that boosted A3G-mediated decreased virus spread will add to mTOR inhibitor effects to diminish uninfected target T cell susceptibility to rebounding infection; and that mTOR inhibition will enhance A3G booster effects on virion A3G content.