SARS-CoV-2-induced humoral immunity through B cell epitope analysis in COVID-19 infected individuals
Shota Yoshida, Chikako Ono, Hiroki Hayashi, Shinya Fukumoto, Satoshi Shiraishi, Kazunori Tomono, Hisashi Arase, Yoshiharu Matsuura, Hironori Nakagami
Abstract
The aim of this study is to understand adaptive immunity to SARS-CoV-2 through the analysis of B cell epitope and neutralizing activity in coronavirus disease 2019 (COVID-19) patients. We obtained serum from forty-three COVID-19 patients from patients in the intensive care unit of Osaka University Hospital (n = 12) and in Osaka City Juso Hospital (n = 31). Most individuals revealed neutralizing activity against SARS-CoV-2 assessed by a pseudotype virus-neutralizing assay. The antibody production against the spike glycoprotein (S protein) or receptor-binding domain (RBD) of SARS-CoV-2 was elevated, with large individual differences, as assessed by ELISA. We observed the correlation between neutralizing antibody titer and IgG, but not IgM, antibody titer of COVID-19 patients. In the analysis of the predicted the linear B cell epitopes, hot spots in the N-terminal domain of the S protein were observed in the serum from patients in the intensive care unit of Osaka University Hospital. Overall, the analysis of antibody production and B cell epitopes of the S protein from patient serum may provide a novel target for the vaccine development against SARS-CoV-2.