VIRUS-LIKE PARTICLES WITH STABILIZED TRIMERIC ENVELOPE FOR PRIME BOOST IMMUNIZATION

到目前为止，唯一显示出对艾滋病毒感染有保护作用的疫苗试验(RV144)是基于 一种痘病毒优质蛋白增强免疫策略。虽然取得的效果不大(~31%)， 这些发现提供了一个强有力的理由来寻求改进主要免疫接种方法和 以更好地了解所获得的保护性免疫的性质。在此应用程序中，我们寻求改进 通过三种独立方法的组合对主要加强免疫的反应：(I)介绍 病毒样颗粒(VLP)上稳定的三聚体Env刺激物作为痘苗病毒PRIME和VLP的免疫原 增强；(Ii)整合来自多个分离株的稳定三聚体包膜(Env)作为多价VLP免疫原 增加响应的广度；以及(Iii)探索可增加SOSIP数量的方法 VLP上的三聚体尖峰。我们的总体工作假设是，Prime-Boost的保护效果 通过优化免疫原和免疫方案提高免疫广度可提高免疫效果 以及中和和非中和抗体反应的效力 人类和/或非人类灵长类动物模型的保护。具体地说，我们假设通过呈现 稳定的三聚体环境蛋白在痘病毒-蛋白质初级增强方案中，我们将能够增强 中和抗体应答，并通过使用多价Env和增加Env刺激物的密度 在VLP免疫原上，我们将进一步放大反应的广度和效力。这个 增强了中和和非中和抗体反应的广度和效力， 包括V1/V2导向的抗体和介导抗病毒效应功能的抗体，如ADCC， 将有助于痘病毒-蛋白质PRIME Boost免疫平台的保护功效。 这项建议的具体目的是：(1)确定结构和抗原性和免疫原性 VLP中稳定的环境三聚体的图谱；(2)确定稳定的环境三聚体是否来自 分离株可以合并到VLP上，如果这种多价疫苗在主要/加强方案中使用时将 增加NAB和非NAB反应的广度；(3)确定细胞质尾部修饰是否将 增加VLP上稳定的环境尖刺的密度，如果增加环境密度将增强宽度和 环境特异性反应的效力；以及(4)检查是否从 之前在兔子身上的研究也可以转化为猕猴。如果成功，从这些研究中获得的见解 将为临床开发疫苗和疫苗策略提供信息，这些疫苗和策略可能比 在RV144中用于防止人类感染艾滋病毒-1。

To date, the only vaccine trial (RV144) that has shown any protective efficacy against HIV acquisition is based on a poxvirus prime–protein boost immunization strategy. Although the efficacy achieved was modest (~31%), these findings provide a strong rationale to seek improvements for the prime-boost immunization approach and to gain better insight on the nature of the protective immunity achieved. In this application, we seek to improve responses to prime boost immunization by a combination of three independent approaches: (i) to present stabilized trimeric Env spikes on virus-like particles (VLP) as immunogens for vaccinia virus prime and VLP boost; (ii) to incorporate stabilized trimeric envelope (Env) from multiple isolates as polyvalent VLP immunogen to increase the breadth of response; and (iii) to explore approaches that may increase the number of SOSIP trimer spikes on VLP. Our overall working hypothesis is that the protective efficacy of prime-boost immunization can be improved by optimizing immunogen and immunization regimen to enhance the breadth and potency of both neutralizing and non-neutralizing antibody responses that have been associated with protection in human and/or non-human primate models. Specifically, we hypothesize that by presenting stabilized trimeric Env on VLP in the poxvirus-protein prime boost regimen, we will be able to enhance neutralizing antibody responses, and by using polyvalent Env and increasing the density of Env spikes on the VLP immunogens, we will further amplify the breadth and the potency of response. The enhanced breadth and potency of both neutralizing and non-neutralizing antibody responses, including V1/V2-directed antibodies and those that mediate antiviral effector functions, such as ADCC, will contribute to the protective efficacy of the poxvirus-protein prime boost immunization platform. The Specific Aims of this proposal are: (1) To determine the structure and the antigenic and immunogenic profiles of stabilized Env trimers incorporated into VLP; (2) To determine if stabilized Env trimers from multiple isolates can be incorporated on VLP and if such polyvalent vaccines when used in a prime/boost regimen will increase the breadth of Nab and non-Nab responses; (3) To determine if cytoplasmic tail modifications will increase the density of stabilized Env spikes on VLP and if increased Env density will enhance the breadth and potency of Env specific responses; and (4) To examine if immunization regimens down-selected from the preceding studies in rabbits can be translated to macaques. If successful, insights obtained from these studies will inform the clinical development of vaccines and vaccine strategies that may be more effective than those used in RV144 to prevent HIV-1 acquisition in humans.