Combining germline-targeting, B cell immunofocusing and Env-Ab co-evolution strategies to induce HIV Envelope V2-apex broadly neutralizing antibodies

项目总结/摘要： 研制有效的艾滋病毒疫苗已证明是一项艰巨的挑战。以前的艾滋病毒战略 疫苗设计旨在引发保护性T细胞应答，非中和抗体，广泛中和抗体， 抗体（bnAb），或三者的某种组合。迄今为止，这三种方法都未能始终如一地 保护非人类灵长类动物（NHP）或人类免受感染。该补助金旨在通过以下方式获得bnAb： 首次将生殖系靶向、免疫聚焦和分子引导相结合的新策略 亲和力成熟这项研究设计从一个日益增长的共识，关键要素，以一个成功的 基于bnAb的疫苗将是其有效结合和激活罕见的幼稚B细胞生殖系前体的能力， bnAb;使这些B细胞对HIV Env三聚体上典型的保守bnAb表位产生免疫反应 并且远离脱靶菌株特异性或三聚体碱基表位;并且使该bnAb谱系成熟或"抛光" 通过分子引导的Env-Ab协同进化过程的反应。本申请中提出的研究设计 解决了这三个基本要求中的每一个，因为它旨在引出靶向高度保守的 HIV-1 V2-顶点部位。主要研究人员（Andrabi和Shaw）组建了一个才华横溢的合作团队， 研究团队在科学发现、生物工程和分子工具开发方面有着良好的记录， 包括V2-apex bnAbs（Burton）的发现、种系靶向V2 apex免疫原的开发 （Andrabi），磷酸丝氨酸连接的明矾纳米颗粒抗原展示的生物工程（Irvine），V2- 顶免疫聚焦黑猩猩猿免疫缺陷病毒（Hahn），CRISPRCas9基因敲入的创建 小鼠（Batista），下一代"设计师" SHIV的开发（Shaw）和临床前-临床转化 （戴伊）。该项目由四个目标组成：目标1将从SHIV中分离HIV包膜V2-apex靶向bnAb 感染的恒河猴，鉴定它们的UCA，并产生表达UCA的敲入小鼠模型， 疫苗评价目标#2将设计新型V2-apex生殖系靶向和免疫聚焦的SOSIP Env三聚体 免疫原，并通过哺乳动物展示饱和诱变和结构指导设计将它们呈现为 可溶性蛋白质或明矾基纳米颗粒用于增强B细胞应答。目标#3将优化生殖系- V2-apex bnAb UCA表达KI小鼠和远系杂交小鼠中的靶向和B细胞免疫聚焦加强策略 RM，并将在SOSIP Env致敏和SHIV感染的RM中识别出可驱动SHIV感染的Env "免疫型"。 中和宽度目标4将首先在KI小鼠中设计和测试，然后在RM中进行关键临床前试验， 一种全SOSIP Env疫苗接种方案，设计用于在大多数情况下引发、加强和亲和力成熟bnAb应答 动物。如果成功，这将是第一个疫苗方案的例子，一贯eliminating bnAb在 这是一个远系繁殖的动物模型，它将代表HIV-1疫苗科学的一个重要滩头阵地， 可以通过我们的翻译合作伙伴迅速过渡到人体测试。

PROJECT SUMMARY/ABSTRACT: The development of an effective HIV vaccine has proven to be a daunting challenge. Previous strategies for HIV vaccine design aimed to elicit protective T cell responses, non-neutralizing antibodies, broadly neutralizing antibodies (bnAbs), or some combination of the three. All three approaches have thus far failed to consistently protect nonhuman primates (NHPs) or humans from infection. This grant aims to elicit bnAbs by means of a novel strategy that combines – for the first time – germline-targeting, immunofocusing and molecularly guided affinity maturation. This study design evolves from a growing consensus that critical elements to a successful bnAb-based vaccine will be its ability to efficiently bind and activate rare naïve B cell germline precursors of bnAbs; to immunofocus these B cell responses to canonical, conserved bnAb epitopes on the HIV Env trimer and away from off-target strain specific or trimer base epitopes; and to mature or “polish” this bnAb lineage response by a process of molecularly guided Env-Ab coevolution. The study design proposed in this application addresses each of these three essential requirements as it aims to elicit bnAbs targeting the highly conserved HIV-1 V2-apex site. The principal investigators (Andrabi and Shaw) have assembled a talented collaborating research team with a strong track record of scientific discovery, bioengineering and molecular tool development, including the discovery of V2-apex bnAbs (Burton), development of germline targeted V2 apex immunogens (Andrabi), bioengineering of phosphoserine-linked alum nanoparticle antigen displays (Irvine), discovery of V2- apex immunofocusing chimpanzee simian immunodeficiency viruses (Hahn), creation of CRISPRCas9 knock-in mice (Batista), development of next-generation “designer” SHIVs (Shaw) and preclinical-clinical translation (Dey). The project consists of four aims: Aim #1 will isolate HIV envelope V2-apex targeted bnAbs from SHIV infected rhesus macaques, identify their UCA’s, and generate UCA-expressing knock-in mouse models for vaccine evaluation. Aim #2 will design novel V2-apex germline-targeted and immunofocused SOSIP Env trimer immunogens and by mammalian display saturation mutagenesis and structure-guided design present them as soluble proteins or alum-based nanoparticles for enhanced B cell responses. Aim #3 will optimize germline- targeting and B cell immunofocusing boost strategies in V2-apex bnAb UCA-expressing KI-mice and outbred RMs, and will identify in SOSIP Env primed and SHIV infected RMs, Env “immunotypes” that can drive neutralization breadth. Aim #4 will design and test, first in KI mice and then in a pivotal preclinical trial in RMs, an all-SOSIP Env vaccination regimen designed to prime, boost and affinity-mature bnAb responses in a majority of animals. If successful, this would be the first example of a vaccine regimen that consistently elicits bnAbs in an outbred animal model, and it would represent an important beachhead in HIV-1 vaccine science, one that could be transitioned rapidly by our translational partner into human testing.