A newly identified linear epitope on non-RBD region of SARS-CoV-2 spike protein improves the serological detection rate of COVID-19 patients

BMC Microbiology

Baisheng Li¹  Min Jiang²  Guilian Li²  Hao Li²  Tiejian Feng²  Xiaohui Wang²  Jianfan He²  Xiujuan Tang²  Yifan Zhong²  Zhengrong Yang²  Shujiang Mei²  Mingyuan Tang³  Tian Tang³  Sicheng Tian³  Sijing Liu³  Chuan Wang³  Yunwen Zhang⁴ 

[1] Guangdong Provincial Center for Disease Control and Prevention, Guangdong, China;Shenzhen Center for Disease Control and Prevention, Shenzhen, China;West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, PR China;Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Department of Public Health Laboratory Sciences, West China School of Public Health, Sichuan University, Chengdu, PR China;West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, PR China;Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Department of Public Health Laboratory Sciences, West China School of Public Health, Sichuan University, Chengdu, PR China;Shenzhen Center for Disease Control and Prevention, Shenzhen, China;

关键词: SARS-CoV-2;    Spike protein;    Epitopes;    Humoral immunity;    Antibody;   

DOI  :  10.1186/s12866-021-02241-y

来源: Springer

【 摘 要 】

BackgroundSerological test is helpful in confirming and tracking infectious diseases in large population with the advantage of fast and convenience. Using the specific epitope peptides identified from the whole antigen as the detection antigen is sensitive and relatively economical. The development of epitope peptide-based detection kits for COVID-19 patients requires comprehensive information about epitope peptides. But the data on B cell epitope of SARS-CoV-2 spike protein is still limited. More importantly, there is a lack of serological data on the peptides in the population. In this study, we aimed to identify the B cell epitope peptides of spike protein and detect the reactivity in serum samples, for further providing data support for their subsequent serological applications.ResultsTwo B cell linear epitopes, P104 and P82, located in non-RBD region of SARS-CoV-2 S protein were identified by indirect ELISA screening of an overlapping peptide library of the S protein with COVID-19 patients’ convalescent serum. And the peptides were verified by testing with 165 serum samples. P104 has not been reported previously; P82 is contained in peptide S21P2 reported before. The positive reaction rates of epitope peptides S14P5 and S21P2, the two non-RBD region epitopes identified by Poh et al., and P82 and P104 were 77.0%, 73.9%, 61.2% and 30.3%, respectively, for 165 convalescent sera, including 30 asymptomatic patients. Although P104 had the lowest positive rate for total patients (30.3%), it exhibited slight advantage for detection of asymptomatic infections (36.7%). Combination of epitopes significantly improved the positive reaction rate. Among all combination patterns, (S14P5 + S21P2 + P104) pattern exhibited the highest positive reaction rate for all patients (92.7%), as well as for asymptomatic infections (86.7%), confirming the feasibility of P104 as supplementary antigen for serological detection. In addition, we analyzed the correlation between epitopes with neutralizing antibody, but only S14P5 had a medium positive correlation with neutralizing antibody titre (rs = 0.510, P < 0.01).ConclusionOur research proved that epitopes on non-RBD region are of value in serological detection especially when combination more than one epitope, thus providing serological reaction information about the four epitopes, which has valuable references for their usage.

【 授权许可】

CC BY