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

项目摘要/摘要： 事实证明，开发有效的艾滋病毒疫苗是一项艰巨的挑战。以前的艾滋病防治策略 疫苗设计旨在诱导保护性T细胞反应，非中和抗体，广泛中和 抗体(BNAbs)，或三者的某种组合。到目前为止，这三种方法都没有一致地 保护非人类灵长类动物(NHP)或人类免受感染。这笔赠款旨在通过一种 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。这项研究的设计从一个日益增长的共识，即关键要素演变为一个成功的 基于bNab的疫苗将能够有效结合和激活稀有的幼稚B细胞种系前体 免疫聚焦这些B细胞对HIV环境三聚体上保守的bNab表位的反应 和远离非靶标菌株的特定或三聚体碱基表位；成熟或“打磨”这个bNab谱系 通过分子引导的Env-Ab共同进化的过程进行响应。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，因为它旨在诱导针对高度保守的 HIV-1V2-顶端位点。首席调查员(安德拉比和肖)召集了一支才华横溢的合作团队 在科学发现、生物工程和分子工具开发方面拥有良好记录的研究团队， 包括V2-顶端bNAbs(Burton)的发现，针对V2顶端免疫原种系的开发 (Andrabi)，磷酸丝氨酸连接的明矾纳米颗粒抗原展示的生物工程(欧文)，发现V2- 顶端免疫聚焦黑猩猩免疫缺陷病毒(HAHN)，产生CRISPRCas9敲入 小鼠(Batista)，下一代“设计者”SHIV的开发(Shaw)和临床前-临床翻译 (Dey)。该项目包括四个目标：Aim#1将从SHIV病毒中分离出HIV包膜V2-顶端靶向bNAbs 感染恒河猴，鉴定其UCA，并建立表达UCA的敲入小鼠模型 疫苗评估。Aim#2将设计新的V2-顶端种系靶向和免疫聚焦的SOSIP环境三聚体 免疫原经哺乳动物展示饱和诱变和结构导向设计呈现为 用于增强B细胞反应的可溶性蛋白质或基于明矾的纳米颗粒。目标3将优化生殖系- V2-顶端bNab UCA表达KI小鼠及其杂交后代的靶向和B细胞免疫增强策略 RMS，并将在SOSIP Env Primed和SHIV感染的RMS中识别可以驾驶的环境“免疫类型” 中和广度。目的#4将首先在Ki小鼠身上设计和测试，然后在RMS的关键临床前试验中， 一种旨在激发、增强和亲和成熟bNab反应的全SOSIP Env疫苗接种方案 关于动物的。如果成功，这将是第一个持续诱导bNAbs的疫苗方案的例子。 一种远缘繁殖的动物模型，它将代表着HIV-1疫苗科学中的一个重要滩头阵地，一个 可以由我们的翻译合作伙伴快速过渡到人体测试。

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.