Figure 1.

Four monoclonal antibodies with non-overlapping epitopes. (A) Competition ELISA for the four monoclonal antibodies against recombinant SARS-CoV-2 RBD protein. The 1st antibodies were unbiotinylated and added in combinations of three antibodies in each well to block the coated RBD, while respective 2nd biotinylated antibodies were used each on its own to detect binding. Results of competition ELISA shown as percent of binding by the 2nd biotinylated antibodies and illustrated in the following colors: black, 0%–25%; dark gray, 26%–50%; light gray, 51%–75%; white, >76%. Representative of two experiments. (B) BLI sensorgrams and kinetics of monoclonal antibodies binding to biotinylated RBD protein of SARS-CoV-2. Four fitting curves are shown with the K_D values. (C) In vitro neutralization assay using authentic SARS-CoV-2 virus in the presence of different concentrations of antibodies XG011, XG014, XG017, XG025. The infection rate was determined by plaque reduction assay. Duplicates of neutralization are presented as means ± SEM