Characterizing HIV-1 Env conformations susceptible to attack by non-neutralizing antibodies

摘要 虽然目前的抗逆转录病毒疗法(ART)能够控制艾滋病毒的复制，但它们无法完全恢复 健康或正常的免疫状态。接受抗逆转录病毒治疗的患者仍然会经历几种并存疾病，包括 心血管疾病、骨骼疾病和认知障碍的增加。最重要的是，治疗 阻断会导致病毒复制重新出现，并发展为艾滋病。因此，新的方法 旨在根除或从功能上治愈艾滋病毒感染是迫切需要的。一个研究不足的战略，以 病毒重新激活后消除潜伏感染细胞依赖于免疫细胞介导抗体的能力- 依赖性细胞毒性(ADCC)。泰国RV144 HIV-1疫苗试验获得31.2%的保护率 效力，使其成为第一个在产生保护性反应方面取得任何程度成功的疫苗试验。后续 分析表明，这种适度的保护与高水平抗体(Abs)的产生有关 ADCC活性，在低血浆IgA环境特异性抗体存在的情况下。这表明ADCC可能已经 有助于在RV144试验中观察到保护。但关键的悬而未决的问题仍然存在， 研究人员使用新的治疗方法或免疫原专门触发ADCC反应：为什么 RV144试用产生如此强烈的ADCC反响？那么HIV-1的CRF01_AE亚型呢？ 在泰国艾滋病流行中占据主导地位，是否会使其特别容易感染ADCC？环境是否会发生构象 是否会影响ADCC回应？回答这些问题将被证明对改进战略的设计至关重要 消灭感染HIV-1的细胞。本提案中描述的研究的长期目标是让 制定利用ADCC应对措施根除艾滋病毒-1感染的新战略。要做到这一点 首先，我们将详细描述易受抗体攻击的环境构象 诱导ADCC，并从不同的HIV-1毒株中确定介导 向这些构象过渡。我们的中心假设是，环境病毒具有内在的下游通道 容易被非中和抗体识别的构象。其中一些，比如反星系团A ABS，具有很强的ADCC活性。为了支持这一假设，我们最近演示了使用抗体结合 分析、低温电子显微镜(Cryo-EM)和单分子Förster共振能量转移(SmFRET) 想象HIV-1Env可以采用对具有强大ADCC的抗体攻击敏感的构象 活动(国家2a)。这一建议依据是对环境国结构的描述 2a，以及由非中和抗体识别的其他构象和中介元素 这些构象的稳定将为消除潜在的艾滋病毒宿主提供新的战略。

SUMMARY While current antiretroviral therapies (ART) are able to control HIV replication, they are unable to fully restore health or a normal immune status. ART-treated individuals still experience several co-morbidities including increased cardiovascular disease, bone disorders, and cognitive impairment. Most importantly, therapy interruption leads to the re-emergence of viral replication and progression to AIDS. Therefore, new approaches aimed at eradicating or functionally curing HIV infection are desperately needed. An under-studied strategy to eliminate latently infected cells after viral reactivation relies on the ability of immune cells to mediate antibody- dependent cellular cytotoxicity (ADCC). The RV144 HIV-1 vaccine trial in Thailand elicited a 31.2% protective efficacy, making it the first vaccine trial with any level of success in generating a protective response. Subsequent analyses indicated that this modest protection was correlated with the generation of antibodies (Abs) with high ADCC activity, in the presence of low plasma IgA Env-specific Abs. This suggests that ADCC may have contributed to the protection observed in the RV144 trial. But key unanswered questions exist that prevent researchers from specifically triggering the ADCC response with novel treatments or immunogens: Why did the RV144 trial generate such a strong ADCC response? What about the CRF01_AE subtype of HIV-1, which predominates the Thai AIDS epidemic, might make it especially susceptible to ADCC? Does Env conformation affect ADCC responses? Answering these questions will prove crucial to the design of improved strategies to eliminate HIV-1-infected cells. The long-term goal of the research described in this proposal is to inform the development of new strategies for utilizing the ADCC response to eradicate the HIV-1 infection. To achieve this goal, we will begin by describing in molecular detail the Env conformations that are susceptible to attack by Abs that induce ADCC, and to determine the structural elements of Env from distinct HIV-1 strains that mediate transition to these conformations. Our central hypothesis is that Env has intrinsic access to downstream conformations that are recognized by easily-elicited non-neutralizing Abs. Some of which, like the anti-cluster A Abs, have potent ADCC activity. In support of this hypothesis, we recently demonstrated using Ab-binding assays, cryo-electron microscopy (Cryo-EM), and single-molecule Förster resonance energy transfer (smFRET) imaging that HIV-1 Env can adopt a conformation that is sensitive to attack by Abs that have potent ADCC activity (State 2A). The rationale underlying this proposal is that characterization of the structure of Env State 2A, as wells as other conformations recognized by non-neutralizing Abs, and the elements that mediate stabilization of these conformations will inform new strategies to eliminate the latent HIV reservoir.