Identification of broadly neutralizing antibody against SARS-CoV-2
Objective:To identify XMA09,a broadly neutralizing antibody against severe acute respiratory syndrome coronavi-rus 2(SARS-CoV-2),and to explore the potential mechanism of XMA09 to broadly neutralize variants of SARS-CoV-2,so as to pro-vide a reference for vaccine design and broadly neutralizing antibody screening against SARS-CoV-2.Methods:XMA09 protein was expressed and purified by ExpiCHO expression system and Protein A chromatography column.The key amino acid sites on receptor binding domain(RBD)recognized by XMA09 were identified by Cryo-EM,and the affinity of XMA09 to Spike protein of SARS-CoV-2 and its variants was detected by indirect ELISA and Surface Plasmon Resonance(SPR).The pseudovirus neutralization assay based on vesicular stomatitis virus(VSV)was used to detect the neutralization ability of XMA09 to wild-type and variants of SARS-CoV-2.Results:In this study,it was found that the epitopes recognized by XMA09 were conservative,who has an excellent binding ability to Spike protein of many kinds of variants,and could neutralize the variants of concern(VOCs),including the widespread BA.4/5.Conclusion:XMA09 is a broadly neutralizing antibody,which has the potential to be used as a therapeutic antibody against SARS-CoV-2,and can provide reference for broad-spectrum vaccine design and antibody drug development against SARS-CoV-2.