HIV-1 Q23.17 Env: Engineering a novel immunogen to elicit broadly neutralizing antibodies

项目总结 在人类中，由HIV-1激发的中和抗体与病毒环境以不同的模式共同进化，在某些情况下 案件的涉及面越来越广。我们发现，在猿人表达时，HIV-1的主要env 22只恒河猴(RMS)中的免疫缺陷病毒(SHIV)诱导的Env-Ab共同进化模式 与人类惊人地相似(科学371：eabd2638,2021)。这包括保守的免疫遗传， 表位识别和精确的环境氨基酸替换、插入和 导致病毒持续存在的删除。一种恒河猴抗体的结构，能够中和49%的 208株，揭示了与人bNAbs PGT145和PCT64类似的V2-顶点识别模式。我们 随后将这项研究扩大到包括150个感染SHV的RMS，这些病毒携带15种不同的原发病毒中的任何一种 这些动物中有24只(16%)产生了针对保守的V2顶点、V3糖链、CD4bs或 融合多肽表位。V2峰是RMS中最常见的bNAb表位。我们的结论是 RMS中Env-Ab的共同进化概括了人bNAbs的发育特征，可能有助于指导和 加快人类HIV-1免疫原设计。从这些临床前数据中，我们确定了HIV-1 Q23.17 Env 作为最稳定地诱导V2峰值bNAbs的免疫原。在这里，我们建议阐明Env-Ab. HIV-1 Q23.17毒株选择性启动、增强和亲和力成熟V2峰的共同进化途径 并将这些发现转化为全SOSIPEnv三聚体疫苗方案，该方案包括 以生殖系为目标的Q23.17环境素数，紧随其后的是谱系设计的Q23.17环境“免疫类型”增强 能够亲和力成熟的B细胞达到广度。具体目标是：(I)破译分子途径 在SHIV.Q23.17感染的RMS中Env-Ab的共同进化导致V2顶端bNAbs的发展，包括 推测的生殖系bNAb前体和谱系中间体及其相应环境的鉴定 结合它们的免疫类型；(Ii)利用哺乳动物显示饱和诱变产生Q23.17包膜蛋白 表现出与多个恒河猴生殖系V2顶端bNAb B细胞前体的增强结合亲和力的变体和 将这些环境基因工程化为纳米颗粒传递的SOSIP三聚体；(Iii)测试种系的免疫原性- 在V2顶端bNAb UCA敲击鼠和近交系小鼠中进行靶向和谱系设计的Q23.17环境SOSIP三聚体 并将最有希望的组合推进到RMS的概念验证临床前疫苗试验；以及 (Iv)在28个RMS进行适当动力的临床前疫苗试验，以测试逆转- 经过设计的B系设计的Q23.17 SOSIP环境三聚体可以启动、增强和亲和成熟的V2顶端bNAb 在RMS中的反应程度优于传统的SOSIP Env免疫原并保护RMS 来自异源病毒的挑战。这些研究的意义可能是深远的：如果我们能够证明 在RMS中使用种系靶向、谱系设计的Q23.17环境SOSIP一致地诱导bNAbs，它将 代表着HIV-1疫苗研究的一个新的滩头阵地，可以迅速转化为人类临床试验。

PROJECT SUMMARY In humans, neutralizing antibodies elicited by HIV-1 coevolve with viral Envs in distinctive patterns, in some cases acquiring substantial breadth. We found that primary HIV-1 Envs, when expressed by simian-human immunodeficiency viruses (SHIVs) in 22 rhesus macaques (RMs), elicited patterns of Env-Ab coevolution strikingly similar to those in humans (Science 371:eabd2638, 2021). This included conserved immunogenetic, structural and chemical solutions to epitope recognition and precise Env-amino acid substitutions, insertions and deletions leading to virus persistence. The structure of one rhesus antibody, capable of neutralizing 49% of a 208-strain panel, revealed a V2-apex mode of recognition like that of human bNAbs PGT145 and PCT64. We subsequently expanded this study to include 150 RMs infected by SHIVs bearing any of 15 different primary HIV-1 Envs; 24 (16%) of these animals developed bNAbs targeting conserved V2 apex, V3 glycan, CD4bs or fusion peptide epitopes. The V2 apex was the most common bNAb epitope targeted in RMs. We concluded that Env-Ab coevolution in RMs recapitulates developmental features of human bNAbs and may serve to guide and accelerate HIV-1 immunogen design for humans. From these preclinical data, we identified HIV-1 Q23.17 Env as the immunogen that most consistently elicited V2 apex bNAbs. Here, we propose to elucidate the Env-Ab coevolutionary pathways by which HIV-1 Q23.17 Env selectively primes, boosts and affinity-matures V2 apex bNAb responses and to translate these findings into an all-SOSIP Env trimer vaccine regimen consisting of a germline-targeted Q23.17 Env prime followed by boosts with lineage-designed Q23.17 Env “imunotypes” capable of affinity-maturing B cells to achieve breadth. Specific aims are: (i) to decipher molecular pathways of Env-Ab coevolution in SHIV.Q23.17 infected RMs that lead to the development of V2 apex bNAbs, including the identification of inferred germline bNAb precursors and lineage intermediates and corresponding Env immunotypes that bind to them; (ii) to use mammalian display saturation mutagenesis to generate Q23.17 Env variants that exhibit enhanced binding affinity to multiple rhesus germline V2 apex bNAb B cell precursors and to engineer these Envs as nanoparticle-delivered SOSIP trimers; (iii) to test the immunogenicity of germline- targeted and lineage-designed Q23.17 Env SOSIP trimers in V2 apex bNAb UCA knockin mice and outbred RMs and to advance the most promising combinations to a proof-of-concept preclinical vaccine trial in RMs; and (iv) to conduct an appropriately powered preclinical vaccine trial in 28 RMs to test the hypothesis that reverse- engineered, B lineage-designed Q23.17 SOSIP Env trimers can prime, boost and affinity mature V2 apex bNAb responses in RMs to an extent that is superior to conventional SOSIP Env immunogens and that protects RMs from heterologous virus challenge. The significance of these studies could be far-reaching: if we can demonstrate consistent induction of bNAbs using germline-targeted, lineage-designed Q23.17 Env SOSIPs in RMs, it would represent a new beachhead for HIV-1 vaccine research that could be translated rapidly into human clinical trials.