Structure-based design of coronavirus subunit vaccines

基于结构的冠状病毒亚单位疫苗设计

基本信息

批准号：
10415747
负责人：
Lanying Du
金额：
$ 72.9万
依托单位：
GEORGIA STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-07-01 至 2023-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10415747
关键词：
Affinity Animal Model Biochemical Biological Models Coronavirus Coronavirus spike protein Data Development Engineering Ensure Epitopes Evaluation Face Future Goals Immune response Immune system Immunize Immunodominant Epitopes Immunologics Individual Infection Knock-in Mouse Length Life Masks Measures Middle East Respiratory Syndrome Coronavirus Molecular Molecular Conformation Monoclonal Antibodies Mus Pathogenicity Play Polysaccharides Proteins Recombinants Research Role SARS coronavirus Site Solid Structure Subunit Vaccines Surface Vaccine Design Vaccines Viral Viral Vector Virion Virus Virus Diseases base betacoronavirus combat coronavirus receptor coronavirus vaccine design immunogenic immunogenicity improved indexing nanoparticle neutralizing antibody nonhuman primate novel novel coronavirus novel strategies preservation protective efficacy receptor binding scaffold vaccine candidate vaccine development vaccine efficacy

项目摘要

Project Summary Viral subunit vaccines are safe and convenient, but generally suffer low efficacy. Our overall hypothesis is that an intrinsic limitation is associated with subunit vaccine designs in which artificially exposed surfaces of subunit vaccines contain epitopes unfavorable for vaccine efficacy. The receptor-binding domain (RBD) of a coronavirus spike protein consists of a core subdomain that serves as the structural scaffold and a receptor- binding motif (RBM) that binds the receptor and contains neutralizing epitopes. The RBDs are prime candidates for subunit vaccine designs. In preliminary studies, we identified epitopes on the core subdomain of MERS coronavirus (MERS-CoV) RBD that were buried in the full-length spike protein but became artificially exposed in recombinant RBDs. We further showed that these epitopes severely reduce vaccine efficacy by inducing strong non-neutralizing immune responses and distracting the host immune system from reacting to the neutralizing epitopes on the RBM. This novel finding reveals an intrinsic limitation of viral subunit vaccines that the vaccine field had been unaware of. In this proposal, we aim to characterize this intrinsic limitation and establish novel approaches to overcome it. We use the RBDs from highly pathogenic coronaviruses, including MERS-CoV and SARS coronavirus (SARS-CoV), as the model system. This proposal contains three major design approaches for coronavirus RBD vaccines. First, we will identify and characterize the artificially exposed unfavorable epitopes on the core subdomain of coronavirus RBDs. To this end, we introduce a novel concept, neutralizing immunogenicity index (NII), to evaluate the contribution of each epitope to the overall vaccine efficacy. We will mask the negative epitopes on the core subdomain through glycan shielding or resurfacing. This design enhances the efficacy of the individually optimized RBD vaccines. Second, we will construct chimeric RBDs containing the core subdomain from one coronavirus RBD as the structural scaffold and the RBM from another coronavirus RBD as the immunogenic sites. The unfavorable epitopes on the core subdomain should have been silenced from the first design approach. The interface of the core subdomain and RBM will be optimized to maximize the stability of the chimeric RBD vaccines. This design prepares us for the emergence of highly pathogenic coronaviruses in the future. Third, we will construct nanoparticle-carried coronavirus RBD vaccines in a way that artificially exposed unfavorable epitopes on the core subdomain are re-buried at the molecular interfaces to enhance the RBD vaccine's efficacy. We will use mice to evaluate the immunogenicity of the above engineered RBD vaccines and will use animal models (including hDPP4-knock-in (KI)) mice and non-human primates) to assess the selected RBD vaccines against live coronavirus challenge. Overall, this research establishes the artificially exposed unfavorable epitopes as the intrinsic limitation of viral subunit vaccines and finds novel approaches to overcome it. Therefore, this research holds the promise of making subunit vaccines a more successful and widely used strategy in combating virus infections.

项目概要病毒亚单位疫苗安全、方便，但疗效普遍较低。我们的总体假设是亚单位疫苗设计存在一个内在的局限性，其中亚单位的人工暴露表面疫苗含有不利于疫苗功效的表位。受体结合域 (RBD) 冠状病毒刺突蛋白由充当结构支架的核心子结构域和受体组成结合基序（RBM），结合受体并含有中和表位。 RBD 是素数亚单位疫苗设计的候选者。在初步研究中，我们鉴定了核心子域上的表位 MERS 冠状病毒 (MERS-CoV) RBD 被埋藏在全长刺突蛋白中，但被人为改造暴露在重组 RBD 中。我们进一步表明，这些表位严重降低了疫苗功效诱导强烈的非中和免疫反应并分散宿主免疫系统的反应 RBM 上的中和表位。这一新发现揭示了病毒亚单位疫苗的内在局限性疫苗领域对此一无所知。在本提案中，我们的目标是描述这种内在的局限性和建立新的方法来克服它。我们使用来自高致病性冠状病毒的 RBD，包括 MERS-CoV 和 SARS 冠状病毒（SARS-CoV）作为模型系统。该提案主要包含三项内容冠状病毒 RBD 疫苗的设计方法。首先，我们将识别并表征人工暴露了冠状病毒 RBD 核心子域上的不利表位。为此，我们向大家介绍一本小说概念，中和免疫原性指数（NII），评估每个表位对整体的贡献疫苗功效。我们将通过聚糖屏蔽或屏蔽核心子域上的负表位重铺表面。这种设计增强了单独优化的 RBD 疫苗的功效。其次，我们将构建含有一种冠状病毒 RBD 核心子结构域的嵌合 RBD 作为结构支架以及来自另一种冠状病毒 RBD 的 RBM 作为免疫原性位点。核心上的不利表位子域应该从第一种设计方法中被静音。核心子域的接口和 RBM 将被优化，以最大限度地提高嵌合 RBD 疫苗的稳定性。这个设计让我们做好准备未来高致病性冠状病毒的出现。第三，我们将构建纳米粒子承载冠状病毒 RBD 疫苗的方式是人为暴露核心子域上的不利表位重新埋入分子界面以增强 RBD 疫苗的功效。我们将使用小鼠来评估上述工程RBD疫苗的免疫原性，并将使用动物模型（包括hDPP4敲入 (KI)) 小鼠和非人类灵长类动物）评估所选 RBD 疫苗对活冠状病毒攻击的抵抗力。总的来说，这项研究将人为暴露的不利表位确定为病毒的内在限制亚单位疫苗并找到克服它的新方法。因此，这项研究有望使亚单位疫苗成为对抗病毒感染的更成功和更广泛使用的策略。