新型针对 SARS-CoV-2 关切变异株的 S2 亚单位特异性抗体，具有广泛的中和活性。

Novel S2 subunit-specific antibody with broad neutralizing activity against SARS-CoV-2 variants of concern.

机构信息

Rare Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Republic of Korea.

Department of Functional Genomics, KRIBB School of Bioscience, University of Science and Technology, Daejeon, Republic of Korea.

出版信息

Front Immunol. 2023 Dec 8;14:1307693. doi: 10.3389/fimmu.2023.1307693. eCollection 2023.

DOI:10.3389/fimmu.2023.1307693

PMID:38143750

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10749193/

Abstract

INTRODUCTION

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), had a major impact on both the global health and economy. Numerous virus-neutralizing antibodies were developed against the S1 subunit of SARS-CoV-2 spike (S) protein to block viral binding to host cells and were authorized for control of the COVID-19 pandemic. However, frequent mutations in the S1 subunit of SARS-CoV-2 enabled the emergence of immune evasive variants. To address these challenges, broadly neutralizing antibodies targeting the relatively conserved S2 subunit and its epitopes have been investigated as antibody therapeutics and universal vaccines.

METHODS

We initiated this study by immunizing BALB/c mice with β-propiolactone-inactivated SARS-CoV-2 (IAV) to generate B-cell hybridomas. These hybridomas were subsequently screened using HEK293T cells expressing the S2-ECD domain. Hybridomas that produced anti-S2 antibodies were selected, and we conducted a comprehensive evaluation of the potential of these anti-S2 antibodies as antiviral agents and versatile tools for research and diagnostics.

RESULTS

In this study, we present a novel S2-specific antibody, 4A5, isolated from BALB/c mice immunized with inactivated SARS-CoV-2. 4A5 exhibited specific affinity to SARS-CoV-2 S2 subunits compared with those of other β-CoVs. 4A5 bound to epitope segment F1109-V1133 between the heptad-repeat1 (HR1) and the stem-helix (SH) region. The 4A5 epitope is highly conserved in SARS-CoV-2 variants, with a significant conformational feature in both pre- and postfusion S proteins. Notably, 4A5 exhibited broad neutralizing activity against variants and triggered Fc-enhanced antibody-dependent cellular phagocytosis.

DISCUSSION

These findings offer a promising avenue for novel antibody therapeutics and insights for next-generation vaccine design. The identification of 4A5, with its unique binding properties and broad neutralizing capacity, offers a potential solution to the challenge posed by SARS-CoV-2 variants and highlights the importance of targeting the conserved S2 subunit in combating the COVID-19.

摘要

简介

严重急性呼吸系统综合症冠状病毒 2（SARS-CoV-2）是导致 2019 年冠状病毒病（COVID-19）的病原体，对全球健康和经济造成了重大影响。针对 SARS-CoV-2 刺突（S）蛋白 S1 亚单位开发了许多病毒中和抗体，以阻止病毒与宿主细胞结合，并被授权用于控制 COVID-19 大流行。然而，SARS-CoV-2 的 S1 亚单位频繁突变使免疫逃避变异体出现。为了应对这些挑战，针对相对保守的 S2 亚单位及其表位的广泛中和抗体已被作为抗体治疗药物和通用疫苗进行研究。

方法

我们通过用β-丙内酯灭活的 SARS-CoV-2（IAV）免疫 BALB/c 小鼠来启动这项研究，以产生 B 细胞杂交瘤。随后，我们使用表达 S2-ECD 结构域的 HEK293T 细胞筛选这些杂交瘤。筛选出产生抗 S2 抗体的杂交瘤，并对这些抗 S2 抗体作为抗病毒药物和研究与诊断的通用工具的潜力进行了全面评估。

结果

在这项研究中，我们从用灭活的 SARS-CoV-2 免疫的 BALB/c 小鼠中分离出一种新型的 S2 特异性抗体 4A5。与其他β-CoV 相比，4A5 对 SARS-CoV-2 S2 亚单位具有特异性亲和力。4A5 结合在 HR1 和 SH 区域之间的七肽重复 1（HR1）和茎螺旋（SH）区域的 F1109-V1133 表位片段上。4A5 表位在 SARS-CoV-2 变体中高度保守，在预融合和融合 S 蛋白中都具有显著的构象特征。值得注意的是，4A5 对变体具有广泛的中和活性，并触发 Fc 增强的抗体依赖性细胞吞噬作用。