Defining the mechanisms of HIV resistance to bNAbs in humans

项目摘要 联合抗逆转录病毒疗法（ART）彻底改变了HIV-1感染的治疗和预防。 然而，抗逆转录病毒疗法并不能根除已确定的感染，全球HIV-1发病率仍然很高， 一直在缓慢下降。因此，寻找新的预防和治疗干预措施仍然是一个很高的目标。 要务近年来，广泛中和抗体（bNAbs）作为每日免疫的长效替代品出现。 抗逆转录病毒疗法是实现长期无治疗HIV-1控制的一种有希望的策略。bNAb与ART的不同之处在于 它们通过其Fc效应结构域参与宿主免疫系统，因此具有潜在的 介导杀死感染细胞并调节或增强HIV特异性免疫应答。然而，bNAb 很容易被HIV-1变异体感染。在HIV-1感染过程中，抗体反应与大的 快速突变的病毒群体，例如对单个抗体具有抗性的变体经常被 遇到的。与这种高水平的多样性相一致，一些临床研究表明，bNAb 单一疗法导致病毒血症的短暂下降，快速选择bNAb抗性病毒株。与此相反， 靶向非重叠Env表位的两种bNAb的组合在参与者中维持了病毒抑制 携带抗体敏感性病毒，已通过ART实现病毒抑制并随后接受 在ART中断期间重复给予bNAb。这些早期研究表明， 但也强调需要更好地了解导致bNAb的病毒逃逸途径 阻力尽管对一些bNAb（即抗V3环）的抗性是基于Env的已知特征，但抗V3环的抗性是基于Env的已知特征。 对于其它bNAb和bNAb的组合，抗性的决定因素定义不清楚。总体 该提案的目标是了解导致bNAb逃逸的途径的多样性，并利用这一点， 指导设计更有效的优化bNAb组合的信息， 抗性变体。本建议有四个相互关联的目标，旨在实现这些目标：（1）确定 使用新开发的方法， 下一代深度测序方法;（2）系统地绘制所有可能的可行bNAb抗性突变 通过生产和测试完整的文库，确定跨病毒株和亚型的逃逸机制 （3）确定可以选择的临床相关的bNAb抗性HIV-1变体的性质 在存在或不存在自体血清的情况下在细胞培养中;（4）开发计算模型， 通过整合从目的1-3获得的序列信息，研究HIV-1 bNAb抗性的机制。

PROJECT SUMMARY Combination antiretroviral therapy (ART) revolutionized the treatment and prevention of HIV-1 infection. However, ART does not eradicate established infection and worldwide HIV-1 incidence rates remain high and have been declining slowly. Thus, the search for novel preventive and therapeutic interventions remains a high priority. In recent years, broadly neutralizing antibodies (bNAbs) emerged as a long-acting alternative to daily ART and as a promising strategy to achieve long-term treatment-free HIV-1 control. bNAbs differ from ART in that they engage the host immune system by virtue of their Fc effector domains and therefore have the potential to mediate killing of infected cells and modulate or enhance HIV-specific immune responses. However, bNAbs are vulnerable to escape by HIV-1 variants. During HIV-1 infection, antibody responses co-evolve with a large population of rapidly mutating viruses, such that variants that are resistant to individual antibodies are frequently encountered. Consistent with this high level of diversity, several clinical studies have demonstrated that bNAb monotherapy leads to transient declines in viremia with rapid selection of bNAb-resistant viral strains. In contrast, a combination of two bNAbs targeting non-overlapping Env epitopes maintained viral suppression in participants harboring antibody sensitive viruses who had achieved viral suppression with ART and subsequently received repeated doses of bNAbs during ART interruption. These early studies demonstrate the potential therapeutic application of bNAbs but also highlight the need to better understand viral escape pathways leading to bNAb resistance. Although resistance to some bNAbs (i.e. anti-V3 loop) is predicated on known features of Env, the determinants of resistance are poorly defined for other bNAbs and for combinations of bNAbs. The overarching goals of this proposal are to understand the diversity of pathways leading to bNAb escape and use this information to guide the design of more effective optimized bNAb combinations that prevent emergence of resistant variants. This proposal has four interrelated aims directed at accomplishing these goals: (1) Determine the sequence elements that lead to viral resistance to bNAb administration in humans using newly developed next generation deep sequencing methods; (2) Systematically map all possible viable bNAb resistance mutations to identify mechanisms of escape across viral strains and subtypes by producing and testing complete libraries of Env mutants; (3) Determine the nature of clinically relevant bNAb-resistant HIV-1 variants that can be selected in cell culture in the presence or absence of autologous serum; (4) Develop computational models that define mechanisms of HIV-1 bNAb resistance by integrating the sequence information obtained from Aims 1-3.