Tian Xingui, Mo Chuncong, Zhou Liling, Yang Yujie, Zhou Zhichao, You Aiping, Fan Ye, Liu Wenkuan, Li Xiao, Zhou Rong
State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou 510182, China.
State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou 510182, China.
Virus Res. 2021 Jul 15;300:198445. doi: 10.1016/j.virusres.2021.198445. Epub 2021 May 5.
The emergency SARS-CoV-2, a member of severe acute respiratory syndrome-related coronaviruses (SARSr-CoV), is still greatly harming the health of mankind. SARS-CoV-2-specific monoclonal antibodies (MAbs), which can identify SARS-CoV-2 from common human coronaviruses, are considered to extensively apply to developing rapid and reliable antigen assays. In this study we generated a rabbit MAb (RAb) detecting SARS-CoV-2 nucleocapsid protein (NP), which has cross-reaction with SARS-CoV-1 NP, but not with NPs of MERS and common human CoVs (OC43, NL63, 229E, and HKU1). With truncated NP fragments and synthesized peptides, the linear epitope detected by RAb was mapped in peptide N4-8, 393-407 amino acid residue (TLLPAADLDDFSKQL) of SARS-CoV-2 NP. This epitope N4-8 was highly conserved in SARSr-CoVs, including SARS-CoV-2, SARS-CoV-1, and bat CoV RaTG13 strain. However, the corresponding peptide of bat SARSr-CoV BtKY72 strain could not be recognized by RAb, which indicates amino acid D399 may be critical for N4-8 epitope detected by RAb. The present study will be conducive to developing reliable diagnosis for SARS-CoV-2 and gaining insights into the function of the SARS-CoV-2 N protein.
新型冠状病毒（SARS-CoV-2）作为严重急性呼吸综合征相关冠状病毒（SARSr-CoV）的一种，仍在极大地危害着人类健康。能从人类常见冠状病毒中识别出SARS-CoV-2的SARS-CoV-2特异性单克隆抗体（MAb），被认为可广泛应用于开发快速可靠的抗原检测方法。在本研究中，我们制备了一种检测SARS-CoV-2核衣壳蛋白（NP）的兔单克隆抗体（RAb），该抗体与SARS-CoV-1的NP有交叉反应，但与中东呼吸综合征冠状病毒（MERS）及人类常见冠状病毒（OC43、NL63、229E和HKU1）的NP无交叉反应。利用截短的NP片段和合成肽，确定了RAb所检测到的线性表位位于SARS-CoV-2 NP的肽段N4-8（氨基酸残基393-407，序列为TLLPAADLDDFSKQL）。该表位N4-8在包括SARS-CoV-2、SARS-CoV-1和蝙蝠冠状病毒RaTG13株在内的SARSr-CoV中高度保守。然而，蝙蝠SARSr-CoV BtKY72株的相应肽段不能被RAb识别，这表明氨基酸D399可能对RAb所检测到的N4-8表位至关重要。本研究将有助于开发针对SARS-CoV-2的可靠诊断方法，并深入了解SARS-CoV-2 N蛋白的功能。
