Abstract:

Comprehensively predicting dominant B cell antigenicepitope of spike（S）protein in SARS-CoV-2 that can cross-immunize with SARS-CoV is to lay the foundation for the development of universal epitope vaccines and associated monoclonal antibodies of S protein in SARS-CoV-2 and SARS-CoV. We employed neighbor-joining method in MEGA5.05 to construct the phylogenetic tree based on the amino acid sequence of S protein in SARS-CoV-2. According to the amino acid sequence alignment of S proteins in SARS-CoV-2 and SARS-CoV and the corresponding results of transmembrane analysis,the region with common epitopes of the two proteins（944-1 213 aa）were screened out. Taking the target region of SARS-CoV-2 Wuhan-Hu-1 strain as the research object,we used the program Protean module in DNAStar software to analyze and predict parameters such as hydrophilicity,flexible region,surface possibility and antigenic index. Considering the spatial structure simulated by online tool Phyre2,we predicted the dominant B cell antigenic epitopes of the S protein in SARS-CoV-2 that cross-immunized with SARS-CoV. The amino acid sequence of the S protein in SARS-CoV-2 was the most similar to the S protein in SARS-CoV（77.5%）,while it was significantly different from the S proteins in other coronaviruses（MERS-CoV,HCoV-HKU1,HCoV-NL63,and HCoV-229E）,and their similarities were lower than 30.3%. The S protein in Wuhan-Hu-1 strain had three hydrophobic cores and might have strong mutability. The antigenic epitopes of target B cell were very likely in amino acid regions at 959-966,973-979,1 003-1 011,1 030-1 037,1 057-1 070,1 079-1 085,1 123-1 132 and 1 174-1 179. The predicted co-antigen epitopes of S proteins in SARS-CoV-2 and SARS-CoV may provide references for the design of universal epitope vaccines,production of monoclonal antibodies and rapid screening of related drugs.

Key words: SARS-CoV-2, SARS-CoV, spike protein, B cell antigenic epitope, cross immunity