Fig. 3. Antibody design and validation based on germline and CDR3 analysis.
a Workflow of antibody identification and functional analysis. Potential antibody sequences were predicted according to screening strategies described in “Materials and methods”. The antibodies were then constructed and expressed for further functional analysis. b Binding curves of five representative mAbs to S-RBD. S309 is a positive control while hIgFC is a negative control. c Binding curves of five representative mAbs to S-ECD. 4A8 is a positive control that was reported to bind the S-ECD of SARS-CoV-2. d Diagram showing the binding of mAbs (EC50 value) to S-ECD determined by ELISA. EC50 values greater than 100 μg/mL are indicated as ">". e Pseudotyped virus neutralization assay to test the neutralization potency with gradient diluted P3V6-1. Infected cells were identified as GFP-positive cells. Images were obtained by using fluorescence microscopy. Scale bars, 40 µm.