CTL选择压力下HIV-1病毒储存库的演进规律及其个性化清除策略研究

The stable latent reservoir for HIV-1 is widely considered the major barrier to curing AIDS. Studies have shown that the "Shock and Kill" strategy, that reactivates the viral reservoir first and then stimulates viral specific cytotoxic T lymphocyte (CTL) response to mediate clearance, is one of the most promising approaches that may lead to a functional cure. Our previous work has found that, besides the small group of patients that started antiretroviral therapy during acute infection, latent reservoirs of the most chronic patients were already dominated by CTL escape mutations located at immunodominant epitopes. Our in vitro and in vivo CTL killing assays had also confirmed that the routine CTL responses targeting dominant epitopes had no effect on the mutated viruses, and that only the CTL responses targeting unmutated subdominant epitopes could clear latently infected cells after reactivation. This finding provides a critical clue for immunogen design of a potential CTL therapeutic vaccine. Therefore in this project, we propose to investigate the evolutionary pattern of CTL escape mutations in the HIV-1 latent reservoir, and answer two important questions: (1) the kinetics of HIV-1 latency establishment during early infection; (2) the strategy that can elicit HIV-1 specific subdominant and broad spectrum CTL responses. Our work will bear important scientific and clinical significance to advance the AIDS cure research.

HIV-1病毒储存库的存在被公认为艾滋病治愈的最大障碍。众多研究表明，先激活储存库，再加强病毒特异杀伤性T细胞（CTL）应答的“Shock and Kill”策略是最有可能达到功能性治愈的方案之一。申请人的前期工作发现，除了少数在急性期就开始抗病毒治疗的患者，绝大多数慢性感染者的病毒储存库已进化出高频率的，发生在免疫优势表位的CTL逃逸突变。通过体外与体内的CTL杀伤实验我们进一步证实，常规的针对优势表位的CTL应答对突变病毒不起作用，只有针对未突变的亚优势表位的CTL应答才能清除激活后的储存库细胞。这为CTL治疗性疫苗的免疫原设计提供了重要的线索。因此，本项目拟通过研究HIV-1病毒储存库CTL逃逸突变的演进规律，回答两个重要科学问题：⑴感染早期储存库形成的动力学特点；⑵HIV-1特异性亚优势及广谱CTL应答的诱导方案。本项目的实施对推进AIDS的功能性治愈研究具有重要的科学与临床意义。

HIV-1潜伏感染可在机体建立长期稳定存在的病毒储存库，导致艾滋病无法治愈。如何削减甚至清除病毒储存库是一个重大科学问题，然而在机体免疫压力下，病毒储存库的动力学变化特征仍有待阐明。本研究致力于揭示抗病毒治疗条件下，感染者体内病毒储存库的动态变化特点，并取得以下主要成果。1.发现一个表达CD161表面分子的CD4+ T细胞亚群在HIV-1的潜伏感染中扮演重要角色，此细胞亚群的克隆扩增可能维持了感染者体内病毒储存库的长期稳定。2.发现随着病情进展，病毒储存库的主要成分滤泡辅助性T细胞中高度富集CXCR4嗜性的潜伏病毒，且其构成比例可作为预测患者病程进展的生物标记物。因此，本研究发现了治疗HIV-1病毒储存库的新靶标细胞亚群，及可预测病毒储存库动态变化的生物标记物，为未来艾滋病功能性治愈的探索提供了重要理论依据。