Characterization of SARS-CoV-2 Variants N501Y.V1 and N501Y.V2 Spike on Viral Infectivity.

SARS-coronavirus 2 (SARS-CoV-2), pathogen of coronavirus disease 2019 (COVID-19), is constantly evolving to adapt to the host and evade antiviral immunity. The newly emerging variants N501Y.V1 (B.1.1.7) and N501Y.V2 (B.1.351), first reported in the United Kingdom and South Africa respectively, raised concerns due to the unusually rapid global spread. The mutations in spike (S) protein may contribute to the rapid spread of these variants. Here, with a vesicular stomatitis virus (VSV)-based pseudotype system, we demonstrated that the pseudovirus bearing N501Y.V2 S protein has higher infection efficiency than pseudovirus with wildtype (WT) and D614G S protein. Moreover, pseudovirus with N501Y.V1 or N501Y.V2 S protein has better thermal stability than WT and D614G, suggesting these mutations of variants may increase the stability of SARS-CoV-2 S protein and virion. However, the pseudovirus bearing N501Y.V1 or N501Y.V2 S protein has similar sensitivity to inhibitors of protease and endocytosis with WT and D614G. These findings could be of value in preventing the spread of virus and developing drugs for emerging SARS-CoV-2 variants.