Figure 1.

Strategy of cloning functional mAbs from single B cells. (A) Schematic diagram of the method for high-throughput cloning of antibody genes from single B cells. VH and VL gene fragments were amplified via Pre-PCR from single B cells’ cDNA. Then, variable region genes, promoter DNA and constant region gene were combined and amplified to produce VH-VL cassettes. The VH-VL cassettes were directly transfected into CHO cell line to express mAbs. Anti-S protein antibodies were identified by ELISA of the supernatants of the transfected cells. (B) MAbs were evaluated for binding and blocking to target by ELISA and HTRF. MAbs blocking ACE2-RBD interaction would cause a reduction in HTRF signal. Apparent binding EC50s are reported as ng/ml and blocking IC50s are reported as μg/ml.