Env evolution in humans and RMs

总结 除了类人猿，印度恒河猴（RM）的免疫系统最接近 对人类的影响。因此，人们普遍认为RM代表了最接近实用的动物模型， 评估对HIV-1的保护性免疫以及可能引发这种保护的疫苗。用于HIV-1的分析 中和抗体（NAb），RM过去曾感染过猴-人免疫缺陷病毒 携带HIV-1 Env的病毒（SHIV）在细胞培养或动物传代中高度适应，或者它们 用多种含有Env的候选疫苗中的任何一种进行免疫， 载体至gp 120单体至可溶性稳定的Env三聚体（SOSIP）。所有这些研究的结果， 日期是相同的：可以产生中和异源1级病毒的Ab，并且在一些情况下， 例如，自体2级病毒，但通常不是构成几乎所有病毒的异源2级病毒。 主要的HIV-1菌株，并负责临床HIV-1传播。令人惊讶的是，没有直接的 实验证据表明RM有可能产生异源2级广泛中和 抗体（bNAb），即使接种了适当的免疫原。因此，HIV-1的主要障碍 疫苗开发的另一个障碍是，没有动物模型系统可以诱导HIV-1 bNAb， 可靠和一致地证明，更不用说以迭代的方式研究合理的疫苗设计。 项目1试图通过利用肖氏实验室最近的发现来克服这一障碍， 新颖的SIV设计策略。项目1的科学前提是，由于大多数bNAb的例子 诱导来自HIV-1的原始株的自然人类感染，这是最可能的诱导bNAb的方法 在RM中是通过感染携带原始HIV-1 Env的SHIV。一个关键假设 我们将测试的是，携带原发性或传递性/创始者（T/F）Env的SHIV将与恒河猴生殖系细胞接合， 和中间祖先B细胞受体（BCR），其与由相同的Env在 人类感染和导致中和抗体产生病毒-抗体协同进化模式 特异性、效力和广度在两个物种中相似。项目1的具体目标是：（一）分析 图33 RM示出了11种新的SHIV的体内复制动力学和NAb应答，已知其Env结合至 靶向V3-聚糖超位点（CH 848、CH 694、CH 040）、V1 V2超位点的人bNAb谱系BCR （CAP 256 SU、ZM 233、WITO、Q23、T250-4、CH 1012）、CD 4 bs（CH 505）或其他（BG 505），并向下选择以 两个SHIV，每个接种到9个RM中;（ii）分析体内复制动力学和env进化 靶向V3-聚糖或V1 V2种系和IA BCR的SHIV途径;和（iii）确定动力学， 多克隆NAb应答的效力和广度以及Env 指纹分析、Env表达克隆和定点诱变。项目1将与核心B紧密联系 项目2和项目3用于样品提供和数据解释。

SUMMARY Excluding the great apes, the immune system of Indian rhesus macaques (RMs) most closely approximates that of humans. Thus, it is widely believed that the RM represents the closest practical animal model for evaluating protective immunity to HIV-1 and vaccines that might elicit such protection. For the analysis of HIV-1 neutralizing antibodies (NAbs), RMs have in the past been infected with simian-human immunodeficiency viruses (SHIVs) that bear HIV-1 Envs that were heavily adapted in cell culture or by animal passage, or they were immunized with any of numerous Env containing candidate vaccines ranging from Env peptides or DNA vectors to gp120 monomers to soluble stabilized Env trimers (SOSIPs). The findings from all such studies to date have been the same: Abs can be generated that neutralize heterologous tier 1 viruses, and in some instances autologous tier 2 viruses, but generally not heterologous tier 2 viruses that constitute virtually all primary HIV-1 strains and are responsible for clinical HIV-1 transmission. Surprisingly, there is no direct experimental evidence that RMs have the potential to develop heterologous tier 2 broadly neutralizing antibodies (bNAbs) even if vaccinated with an appropriate immunogen. Thus, a major roadblock to HIV-1 vaccine development is that there is no animal model system where the elicitation of HIV-1 bNAbs can be reliably and consistently demonstrated, let alone be studied in an iterative fashion for rational vaccine design. Project 1 seeks to overcome this roadblock by capitalizing on recent discoveries by the Shaw lab regarding novel SHIV design strategies. The scientific premise of Project 1 is that since most examples of bNAb elicitation come from natural human infection by primary strains of HIV-1, the most likely means to elicit bNAbs in RMs is by infection with SHIVs bearing primary HIV-1 Envs in their native conformations. A key hypothesis that we will test is that SHIVs bearing primary or transmitted/founder (T/F) Envs will engage rhesus germline and intermediate ancestor B cell receptors (BCRs) that are orthologous to those engaged by the same Envs in human infection and that patterns of virus-Ab coevolution leading to the development of neutralizing antibody specificity, potency and breadth will be similar in both species. Specific Aims of Project 1 are to: (i) analyze in 33 RMs the in vivo replication kinetics and NAb responses of 11 novel SHIVs whose Envs are known to bind to human bNAb lineage BCRs targeting the V3-glycan supersite (CH848, CH694, CH040), V1V2 supersite (CAP256SU, ZM233, WITO, Q23, T250-4, CH1012), CD4bs (CH505) or other (BG505), and down-select to two SHIVs for inoculation into 9 RMs each; (ii) analyze in vivo replication kinetics and env evolutionary pathways of SHIVs targeting V3-glycan or V1V2 germline and IA BCRs; and (iii) determine the kinetics, potency and breadth of polyclonal NAb responses and map epitope specificities by a combination of Env fingerprinting, Env-expression cloning, and site-directed mutagenesis. Project 1 will link closely with Cores B and C for sequencing and bioinformatics and Projects 2 and 3 for sample provision and data interpretation.