Elicitation of broad immunity using VLPs with consensus envs

描述（由申请人提供）：艾滋病疫苗开发面临的最大挑战之一是不同地理位置的HIV-1流行人群的内在多样性，以及需要开发能够引起对变异HIV-1毒株的持久保护性免疫的疫苗。虽然在所有病毒蛋白中观察到变异，但最大的多样性定位于病毒包膜糖蛋白，这显然反映了这些蛋白在引发宿主免疫识别和应答中的主导作用，从而导致包膜蛋白在持续感染期间的渐进进化。在当前的应用中，我们设计了新型病毒样颗粒（VLP）免疫原，可以优化粘膜和全身Env特异性免疫反应，以评估恒河猴通过阴道暴露（HIV-1传播的最常见途径）对异源SHIV攻击的保护作用。全球）。我们已经构建了DNA质粒以表达来自SHIV基因序列的VLP，其中每个DNA构建体表达来自单个DNA质粒的非感染性慢病毒VLP。每个VLP基因插入物表达gag、pol、env、vpu、达特和rev基因序列，这些基因序列通过质粒DNA从巨细胞病毒立即早期启动子表达。因此，VLP mRNA剪接和核输出将由病毒机制控制，并且翻译的蛋白质有效地从转染的细胞分泌VLP。几个安全突变已经被设计到VLP的骨架中，以符合美国食品和药物管理局关于人类使用HIV-1 DNA疫苗的指南。在该提议中，表达SHIV VLP的基因插入物将从DNA表达。此外，将从用相同DNA质粒转染的灵长类动物细胞的上清液中纯化SHIV VLP。我们建议构建和表征SHIV VLP-DNA质粒的文库，每个质粒含有不同的利用CCR 5（RS）的HIV-1进化枝B或进化枝C包膜糖蛋白。恒河猴将以初免/加强方案（DNA初免/颗粒加强）接种疫苗，以引发体液免疫和细胞免疫，并评价对异源进化枝B SHIV攻击的保护。该提议的目的是评估和比较具有初级包膜的VLP免疫原之间的免疫应答诱导与具有代表共有包膜序列（进化枝B或进化枝C）的包膜的VLP免疫原引起的免疫应答。还将评估SHIV-1 VLP对异源SHIV攻击的免疫和保护的激发。使用共有包膜作为天然寡聚体允许将由共有包膜引起的保护性免疫与由与攻击病毒错配的初级寡聚包膜的混合物引起的保护性免疫进行比较。最后，将用进化枝B SHIV攻击评价由含有代表进化枝C的共有包膜序列的包膜的SHIV-1 VLP（Con C）引发的免疫应答的广度和保护效力。

DESCRIPTION (provided by applicant): Among the greatest challenges facing AIDS vaccine development is the intrinsic diversity among circulating populations of HIV-1 in various geographical locations and the need to develop vaccines that can elicit enduring protective immunity to variant HIV-1 strains. While variation is observed in all of the viral proteins, the greatest diversity is localized to the viral envelope glycoproteins, evidently reflecting the predominant role of these proteins in eliciting host immune recognition and response that result in progressive evolution of the envelope proteins during persistent infection. In the current application, we have designed novel virus-like particle (VLP) immunogens that can optimize mucosal and systemic Env-specific immune responses for evaluation against protection from heterologous SHIV challenge in rhesus macaques by vaginal exposure (the most common route of HIV-1 transmission worldwide). We have constructed DNA plasmids to express VLPs from SHIV gene sequences where each DNA construct expresses a non-infectious lentiviral VLP from a single DNA plasmid. Each VLP gene insert expresses the gag, pol, env, vpu, tat, and rev gene sequences that are expressed from a cytomegalovirus immediate-early promoter via plasmid DNA. Thus, VLP mRNA splicing and nuclear export will be controlled by viral mechanisms and translated proteins efficiently secrete VLPs from transfected cells. Several safety mutations have been engineered into the backbone of the VLP to match the U.S. Food and Drug Administration guidelines for the use of HIV-1 DNA vaccines for human use. In this proposal, gene inserts expressing SHIV VLPs will be expressed from DNA. In addition, SHIV VLPs will be purified from the supernatant of primate cells transfected with the same DNA plasmids. We propose to construct and characterize a library of SHIV VLP-DNA plasmids, each containing a different CCR5 (RS)-utilizing clade B or clade C envelope glycoprotein of HIV-1. Rhesus macaques will be vaccinated in a prime/boost regimen (DNA prime/particle boost) for the elicitation of both humoral and cellular immunity, and protection from heterologous clade B SHIV challenge will be evaluated. The goals of this proposal are to assess and compare the induction of immune responses between VLP immunogens with primary envelopes to the elicitation of immunity by VLP immunogens with an envelope representing the consensus envelope sequences (clade B or clade C). SHIV-1 VLPs will also be assessed for elicitation of immunity and protection to a heterologous SHIV challenge. The use of a consensus envelope as a native oligomer allows for the comparison of protective immunity elicited by consensus envelopes to that elicited by a mixture of primary oligomeric envelopes that are mismatched to the challenge virus. Finally, the breadth and protective efficacy of immune responses elicted by a SHIV-1 VLP containing an envelope representing the consensus envelope sequence of clade C (Con C) will be evaluated with a clade B SHIV challenge.