HIV感染尚无理想疫苗，亦无可行根治方法，需终身用药。广谱中和抗体（bnAb）是疫苗及免疫治疗的重要目标，全球已筛选到数十种bnAb，但迄今仍无法通过主动免疫诱导人体产生bnAb。本团队及国外研究均发现人发生HIV超感染后，常获得广谱中和能力，多个已知bnAb来自超感染者。由于异源抗原序贯刺激，超感染者bnAb产生机理可能与单毒株感染者不同，具体过程尚未解明。本研究拟从急性感染队列中扩大筛选超感染者，以下一代测序、单基因组扩增分析超感染者体内env基因进化轨迹；以假病毒中和实验筛选超感染者中的精英中和者，揭示其自体及异体中和活性发展历程及与病毒进化的时序关系；以酵母表面展示抗原片段文库、突变假病毒中和、多肽及表位特异性抗原封闭试验解析超感染者bnAb识别表位及演变过程；通过病毒与bnAb共进化研究，揭示决定bnAb发生发展的关键变异病毒特征，为精准设计序贯免疫策略诱导bnAb提供科学依据。

By far, there is neither ideal vaccine for HIV-1 prevention nor practical way for HIV cure. Broadly neutralizing antibodies (bnAbs) are important targets for both vaccine and immunotherapy in HIV infection. Although dozens of bnAbs have been identified from natural HIV-1 infected donors in the world, unfortunately, bnAbs still cannot be elicited in the human body through active immunization by far. Both our group and the foreign researchers found that HIV-1 infected persons often developed broadly neutralizing activities after super infected with another heterogeneous HIV-1. Moreover, some bnAbs have been identified from super infected cases. Because heterologous antigens are provided in HIV-1 super infected cases, the mechanism of bnAb development among super infection maybe different from single strain infected cases, but the detail process still need further study. In this study, an expanded screening will be done on patients from mem who have sex with men acute HIV infection cohort previously established by our group. Next generation sequencing and single-genome amplification will be used to analyze the trajectory of viral evolution among super infected cases since the initial HIV infection. In vitro pseudovirus neutralization assay will be used to identify elite neutralizer and the dynamics of heterologous neutralization activities among the super infected cases. Pseudotyped viruses based on autologous transmitted founder virus and representative mutant/recombinant strains among super infected cases will be used to analyze the initiation and development of autologous neutralizing activities. The potential temporal link between the viral evolution and neutralizing activities will be explored. The epitope mapping of bnAbs and their evolution processes among super infected cases will be first explored with yeast antigen display library, then verified with env clones containing known epitope-specific knockout mutations, peptide binding and epitope-specific antigens blocking assays. The trajectories of targeting epitope will be compared with the sites of autologous viral mutations. Through exploring the viral features that determine the key points of bnAbs initiation and maturation, this study will provide basis on precisely designing sequential immune strategy with multiple HIV envelope immunogens aiming at eliciting bnAb against HIV-1 in human body.