Extended Data Fig. 1 ∣. The epitopes of IgG1 monoclonal antibodies used for engineering and additional characterizations of IgM and IgA1.

a, The RBD is shown as a cartoon with the core region coloured in grey and the receptor-binding motif (RBM) coloured in red. b, Summary of the binding region on the RBD, key epitope residues and cross-reactivity to SARS-CoV of the six monoclonal antibodies. These epitope residues were mapped using an alanine-scanning RBD mutant library in a previous study¹. c, ELISA binding to RBD by IgG1, IgA1 and IgM isotypes of the indicated monoclonal antibodies. Data are mean of duplicate wells. d, Neutralization of live SARS-CoV-2 by IgG1, IgA1 and IgM monoclonal antibodies at 1 μg ml⁻¹. Data are mean ± s.d. of triplicates.