Functional Differences Among the Spike Glycoproteins of Emerging Sars-Cov-2 Variants B.1.1.7, B.1.351, P.1 and B.1.1.248

We compared the functional properties of spike (S) glycoproteins from the original SARS-CoV-2 strain (D614) (Wuhan, China), the globally dominant D614G strain and emerging geographic variants:  B.1.1.7 (United Kingdom), B.1.351 (South Africa), P.1 (Brazil), and B.1.1.248 (Brazil/Japan). Compared with D614G, the emerging variants exhibited increased affinity for the receptor, ACE2, and increased ability to infect cells with low ACE2 levels.  All variants lost infectivity similarly at room temperature and 37°C; however, in the cold, B.1.1.7 was more stable, and P.1 and B.1.1.248 were less stable. Shedding of the S1 glycoprotein from the spike contributed to virus inactivation in the cold.  B.1.351, P.1 and B.1.1.248 were neutralized by convalescent and vaccinee sera less efficiently than the other variants. Spike glycoprotein properties such as requirements for ACE2 levels on the target cell, functional stability in the cold and resistance to host neutralizing antibodies potentially contribute to the outgrowth of emerging SARS-CoV-2 variants. Funding Information: This study was supported by the National Institutes of Health and by a gift from the late William F. McCarty-Cooper. Declaration of Interests: The authors declare no competing interests.