Combined adjuvant approaches for enhancement of SARS-CoV-2 vaccine efficacy

项目摘要/摘要 与新冠肺炎相关的高发病率和死亡率继续突显出有效的 针对SARS-CoV-2的疫苗。虽然一些有希望的候选人获得了EUA，但出现了更多 影响疫苗效力的可传播变种突显了仍然存在的几个挑战。一个 成功的疫苗必须：1.在自然感染冠状病毒时产生强大的持久保护作用 通常导致相对短暂的免疫，2.随着病毒变异的积累而给予广泛的免疫，3. 为老年人提供强大的免疫力，以及4.鉴于过去观察到的冠状病毒增强的疾病，保持安全 疫苗。为了应对这些挑战，本提案旨在开发一种安全、有效、可快速翻译的 使用合理设计的组合佐剂靶向阵列的SARS-CoV-2疫苗佐剂系统 参与抗病毒免疫的关键先天受体途径。佐剂是促进FAST的有力工具， 对特定病原体最有效的持久和定性反应，特别是在免疫挑战 个人。自然病毒感染通过激活Toll-、RIG-I-和 Nod样受体(TLRs、RLRs、NLRs)。因为诱导适当的先天反应对于长效至关重要 适应性免疫和塑造正确的免疫反应类型，我们将测试使用 整合这些途径的激动剂的组合将导致体液和细胞反应的改善 走向SARS-CoV-2。为了实现这一点，我们将结合一种基于纳米乳剂的佐剂(NE)，它可以激活 TLRs和NLRP3与RIG-I的RNA激动剂(IVT DI)。我们已经证明了同时激活 TLRs、RIG-I和NLRP3与NE/IVT DI联合诱导协同免疫应答 细胞免疫。在强有力的初步数据的指导下证明了这种联合佐剂的有效性 改进流感病毒疫苗接种的方法，以及我们对SARS-CoV-2抗原的初步研究，我们将 开发这种佐剂用于SARS-CoV-2疫苗有两个特定目的。在目标1中，我们将描述免疫 NE/IVT DI与多种SARS-CoV-2抗原通过肠外和粘膜途径诱导的免疫应答 优化配方和接种途径。在目标2中，我们将确定其保护效果和安全性 优化的疫苗平台在SARS-CoV-2挑战模型中的领先地位，并确定关键的保护相关因素。 越来越多的数据表明，SARS-CoV-2引起了一种微弱的天生反应，关键的抗病毒活性很差 途径，这可能是造成免疫反应的大小和持久性的巨大差异的原因 康复的病人。通过这种有针对性的方法，我们希望推动更强大和持久的免疫力，同时 避免免疫反应促进疫苗相关病理。NE佐剂和几种RIG-I激动剂 已经在I期人体试验中证明了良好的安全性。因此，我们期待着成功完成 这项工作将导致一种可快速翻译和递送的与多种SARS-CoV-2兼容的佐剂 并对保护性SARS-CoV-2免疫的关键影响因素提供了亟需的洞察力。

PROJECT SUMMARY/ABSTRACT The high morbidity and mortality associated with Covid-19 continues to underscore the importance of effective vaccines against SARS-CoV-2. While a few promising candidates have received EUAs, the emergence of more transmissible variants which have impacted vaccine efficacy highlight the fact that several challenges remain. A successful vaccine must: 1. induce robust long-lasting protection when natural infection with coronaviruses generally leads to relatively short-lived immunity, 2. impart broad immunity as viral mutations accumulate, 3. provide potent immunity in the elderly, and 4. be safe in light of enhanced disease observed with past coronavirus vaccines. To address these challenges, this proposal aims to develop a safe, effective, and rapidly translatable adjuvant system for SARS-CoV-2 vaccines using a rationally designed combination adjuvant to target an array of key innate receptor pathways involved in antiviral immunity. Adjuvants are powerful tools for promoting fast, durable and qualitative responses most effective for a particular pathogen, especially in immune-challenged individuals. Natural viral infection stimulates strong immune responses through activation of Toll-, RIG-I-, and NOD-like receptors (TLRs, RLRs, NLRs). As induction of appropriate innate responses is crucial for long-lasting adaptive immunity and for shaping the correct types of immune responses, we will test the hypothesis that using a combination of agonists that integrate these pathways will lead to improved humoral and cellular responses towards SARS-CoV-2. To achieve this, we will combine a nanoemulsion-based adjuvant (NE) that activates TLRs and NLRP3 with an RNA agonist of RIG-I (IVT DI). We have demonstrated that simultaneous activation of TLRs, RIG-I, and NLRP3 with NE/IVT DI induces a synergistic immune response with magnified TH1-biased cellular immunity. Guided by strong preliminary data demonstrating the effectiveness of this combined adjuvant approach for improving influenza virus vaccination, and our initial studies with SARS-CoV-2 antigens, we will develop this adjuvant for use in a SARS-CoV-2 vaccine in two specific aims. In Aim 1, we will profile the immune responses elicited by NE/IVT DI with multiple SARS-CoV-2 antigens through parenteral and mucosal routes to optimize formulations and vaccination routes. In Aim 2, we will determine the protective efficacy and safety of the optimized lead vaccine platforms in challenge models of SARS-CoV-2 and define key correlates of protection. Increasing data suggests that SARS-CoV-2 elicits a weak innate response, with poor activation of critical antiviral pathways, which likely contributes to the large variability in magnitude and durability of immune responses in recovered patients. With this targeted approach, we expect to drive more robust and durable immunity while avoiding immune responses promoting vaccine related pathology. The NE adjuvant and several RIG-I agonists have demonstrated good safety profiles in phase I human trials. Thus, we expect that successful completion of this work will lead to a rapidly translatable and deliverable adjuvant compatible with multiple SARS-CoV-2 vaccine candidates, and provide much needed insight on the key effectors of protective SARS-CoV-2 immunity.