Env-Ab coevolution in SHIV infected RMs leading to V3 glycan bNAbs

项目摘要 合理设计HIV-1疫苗的一个主要障碍是缺乏合适的灵长类动物模型， 中和抗体（bNAb）可以被一致地诱导，并且潜在的分子、生物和 以迭代方式研究免疫机制。由于大多数HIV-1 bNAb来自人类， 感染HIV-1后，我们假设在灵长类动物中引发bNab的一种方法可能是感染恒河猴， 猕猴（RM）与猴-人免疫缺陷病毒（SHIV）株，携带原发性或 传播/创始人HIV-1 Env，包括在人类中诱导bNAb的那些。SHIV感染的RM可以 可以用来评估不同的HIV-1 Env引发bNAb的潜力， bNAb谱系和引发它们的同源Env的途径，从而作为一个“分子向导”， 合理的疫苗设计我们实验室最近在SIV设计方面的创新使这种实验策略成为可能。 可测试的在这次更新申请中，我们发现150例感染携带不同病毒的SHIV的RM中有24例，即16%， 原代HIV-1 Env产生了靶向V3聚糖、V2顶点、CD 4 bs或融合肽表位的bNAb。九 这些动物产生V3聚糖bNAb。从这个广泛的数据集中，我们确定了HIV-1 CH 848和 BG505.N332 Envs作为免疫原，在RM中最一致地引发V3聚糖bNAb。我们进一步研究发现 通过减少V1的长度和V1中潜在的N-连接聚糖的数量（命名为CH848.dV1 和BG505.N332.dV1），我们可以提高SHIV中V3聚糖bNAb的诱导频率和速度， 感染RM。基于这些发现，我们在本项目中提出了检验RM感染 通过SHIV.CH848.dV1或SHIV.BG505.N332.dV1将选择性地引发V3聚糖bNA B谱系B细胞前体， 并通过Env-Ab共同进化的过程，使这些反应成熟，以实现中和宽度。 此外，通过鉴定选择V3聚糖bNAb亲和力成熟的进化的Env中间体，我们可以 设计基于谱系的Env免疫原，当构建为SOSIP Env三聚体并用于免疫时， 远系繁殖RM将引发对异源病毒攻击具有保护性的V3聚糖bNAb。具体目标 （i）在SHIV感染的RM中，破译Env-Ab协同进化的分子途径，导致 V3聚糖bNAb的鉴定，包括推断的种系bNAb前体、bNAb谱系 选择亲和力成熟和中和宽度的Env中间体和进化的Env中间体;（ii） 评价纳米颗粒递送的、种系靶向的CH848.dV1和BG505.N332.dV1 SOSIP Env 三聚体引发V3聚糖bNAb谱系前体，并用于随后的同源SHIV感染以选择 亲和力成熟度和中和广度;以及（iii）进行自动化驱动的概念验证 在RM中进行的疫苗试验，检验了生殖系靶向的、B谱系设计的SOSIP Env三聚体可以 在上级于常规SOSIP的程度上引发、加强和亲和力成熟V3聚糖bNAb应答 Env免疫原，保护RM免受异源病毒攻击。

PROJECT SUMMARY A major roadblock to rational HIV-1 vaccine design is the lack of a suitable primate model in which broadly neutralizing antibodies (bNAbs) can be consistently induced and the underlying molecular, biological and immunological mechanisms studied in an iterative fashion. Since most HIV-1 bNAbs have come from humans infected by HIV-1, we hypothesized that one means to elicit bNabs in primates might be by infecting rhesus macaques (RMs) with simian-human immunodeficiency virus (SHIV) strains that bear primary or transmitted/founder HIV-1 Envs, including those that induced bNAbs in humans. SHIV infected RMs could then be employed to assess the potential of different HIV-1 Envs to elicit bNAbs and to characterize the coevolutionary pathways of bNAb lineages and cognate Envs that elicited them, thereby serving as a “molecular guide” for rational vaccine design. Recent innovations in SHIV design by our lab have made this experimental strategy testable. In this renewal application, we show that 24 of 150, or 16%, of RMs infected by SHIVs bearing different primary HIV-1 Envs developed bNAbs targeting V3 glycan, V2 apex, CD4bs or fusion peptide epitopes. Nine of these animals developed V3 glycan bNAbs. From this extensive dataset, we identified HIV-1 CH848 and BG505.N332 Envs as immunogens that most consistently elicited V3 glycan bNAbs in RMs. We further showed that by reducing the length of V1 and the number of potential N-linked glycans in V1 (designated CH848.dV1 and BG505.N332.dV1), we could enhance the frequency and speed of induction of V3 glycan bNAbs in SHIV infected RMs. Based on these findings, we propose in this project to test the hypothesis that infection of RMs by SHIV.CH848.dV1 or SHIV.BG505.N332.dV1 will selectively prime V3 glycan bNAb lineage B cell precursors, and through a process of Env-Ab coevolution, mature these responses to achieve neutralization breadth. Moreover, by identifying evolved Env intermediates that select for V3 glycan bNAb affinity maturation, we can design lineage-based Env immunogens that, when constructed as SOSIP Env trimers and used to immunize outbred RMs, will elicit V3 glycan bNAbs that are protective against heterologous virus challenge. Specific Aims are: (i) to decipher molecular pathways of Env-Ab coevolution in SHIV-infected RMs that lead to the development of V3 glycan bNAbs, including the identification of inferred germline bNAb precursors, bNAb lineage intermediates and evolved Env intermediates that select for affinity maturation and neutralization breadth; (ii) to evaluate the ability of nanoparticle-delivered, germline-targeted CH848.dV1 and BG505.N332.dV1 SOSIP Env trimers to prime V3 glycan bNAb lineage precursors and for subsequent homologous SHIV infection to select for affinity maturation and neutralization breadth; and (iii) to conduct a statistically-powered, proof-of-concept vaccine trial in RMs testing the hypothesis that germline-targeted, B lineage-designed SOSIP Env trimers can prime, boost and affinity mature V3 glycan bNAb responses to an extent that is superior to conventional SOSIP Env immunogens and that protects RMs from heterologous virus challenge.