Figure 4.

Binding kinetics and functional testing of Spike-specific antibodies against the RBD of the SARS-CoV-2

(A–C) Biolayer interferometry curves for CR3022, 154C, and 240C with 3-fold dilutions. Streptavidin biosensors were coated with biotinylated RBD, then blocked with 1 μM D-Biotin in kinetics buffer. Negative binding curves for 341C and 540C shown in Figure S5. Curve fitting was performed using 1:1 binding model in ForteBio Analysis HT 10.0 software.

(D) Summary of quantified binding kinetics of Spike monoclonal antibodies from BLI experiment.

(E) Neutralization assay 50% neutralization values against live SARS-CoV-2 by focus-forming assay and SARS-CoV-2 spike pseudotyped lentivirus by fluorescence microscopy. EC₅₀ values represent triplicate experiments (n = 3). 1v6 is positive control from COVID-19 patient convalescent serum collected at day 14. The concentration of all monoclonal antibody stocks was 1 mg/mL. 154C and 240C showed only partial neutralization at the highest concentration tested (1:10 dilution), whereas 341C, 540C, and CR3022 failed to reliably neutralize pseudotyped virus at this dilution.

See also Figures S5 and S6.