Resistance of SARS-CoV-2 variants to neutralization by monoclonal and serum-derived polyclonal antibodies

Recombinant SARS-CoV-2 variants possessing mutations in the S gene derived from United Kingdom, South African, Brazilian and some other strains were generated. These viruses were subjected to the in vitro culture cell infection experiments to study the effectiveness of neutralizing monoclonal or serum-derived polyclonal antibodies. Some variants, particulary South Africa strain, showed reduced sensitivity against the neutralization by monoclonal and polyclonal antibodies. A mutation E484K located in the receptor-binding domain of spike protein was found to be one of the key factors that determines the ineffectiveness of neutralizing antibody.