Development of Epitope-Targeted SARS-CoV-2 Vaccines

目前急需一种针对SARS-CoV 2的疫苗。我们已经开发了一种基于RNA病毒的病毒样颗粒（VLP）的疫苗平台技术，如MS 2，PP 7，AP 205和QP 3。当在这些生物纳米颗粒上多价展示时，肽和蛋白质抗原获得高水平的免疫原性。它们引发对几乎任何展示的抗原的高滴度和长寿命的抗体应答。此外，VLP平台具有快速响应潜力，可快速应对新出现的威胁。在这里，我们描述了一种方法来展示SARS-CoV 2表位，并测试它们在小鼠中引发中和和保护性抗体的能力。我们的方法包括三个具体的目标：在目标1中，我们将确定候选疫苗表位的SARS-CoV 2和赋予他们高免疫原性，通过展示他们在VLP。该病毒与SARS-CoV 1具有足够的序列和结构同源性，使我们能够根据其中和抗体靶点的知识推断可能的中和表位。因此，我们描述了用于展示和优化刺突蛋白表位的策略，我们预测刺突蛋白表位将引发分别抑制病毒进入中的两个基本步骤-受体结合和病毒-细胞融合的抗体。在目标2中，我们将用候选VLP免疫小鼠，并将使用ELISA来定量产生的抗体应答，测试血清与重组刺突蛋白和代表所选表位的合成肽的反应。在目标3中，将通过培养细胞中的空斑减少中和试验检测血清的中和活性。随后，我们将给转人ACE 2（SARS-CoV 2受体）基因的小鼠接种疫苗，并测试它们抵抗SARS-CoV 2感染的能力。

A vaccine against SARS-CoV2 is badly needed. We have developed a vaccine platform technology based on virus-like particles (VLPs) of RNA phages like MS2, PP7, AP205 and Qß. When displayed multivalently on these bionanoparticles, peptide and protein antigens acquire a high level of immunogenicity. They elicit high titer and long-lived antibody responses to virtually any displayed antigen. Moreover, the VLP platform has rapid response potential to quickly counter emerging threats. Here we describe an approach to the display of SARS-CoV2 epitopes, and tests of their ability to elicit neutralizing and protective antibodies in mice. Our approach consists of three specific aims: In Aim 1, we will Identify candidate vaccine epitopes for SARS-CoV2 and endow them with high immunogenicity by displaying them on VLPs. This virus shares sufficient sequence and structural homology with SARS-CoV1 to allow us to infer likely neutralizing epitopes from knowledge of the targets of its neutralizing antibodies. Accordingly, we describe strategies for display and optimization of spike protein epitopes we predict will elicit antibodies that will separately inhibit two essential steps in virus entry - receptor binding and virus-cell fusion. In Aim 2, we will immunize mice with candidate VLPs and will use ELISA to quantify the resulting antibody responses, testing the reaction of sera with recombinant spike protein and with synthetic peptides representing the chosen epitopes. In Aim 3, the neutralization activity of sera will be tested by plaque reduction neutralization tests in cultured cells. Subsequently, we will vaccinate mice transgenic for human ACE2 (the SARS-CoV2 receptor) and test their abilities to resist the effects of SARS-CoV2 infection.