Figure 1.

Schematic overview of the rapid and efficient NAbs screening system. Rapid NAbs screening workflows and timelines are shown, representing the multiple processes conducted in order. The PBMC were isolated from collected convalescent patients’ blood, and the RBD-specific memory B cells in the PBMC were sorted as single cells via flow cytometry (day 1). Then, the IgG heavy and light chains of mAb genes were amplified by RT-PCR on the same day. 2^nd PCR products were cloned into the linear expression cassettes (day 2). HEK293T cells expressed antibodies by transient transfection with equal amounts of paired heavy and light chain linear expression cassettes and culture for 48 hours. The supernatants were used to detect the antigen reactivity of antibodies by ELISA in 384-well plates (day 4). The neutralizing activities of antibodies were measured with pseudovirus bearing SARS-CoV-2 S in 96-well plates (day 6). Plasmids expressing potential neutralizing Abs were transfected into Exi293F cells for the large-scale production of Ab proteins. The cell supernatants of Exi293F cells were collected, and the antibody proteins were purified by protein G beads. Antigen reactivity, neutralizing activity, and binding affinity were further accessed via ELISA, competitive ELISA, and surface plasmon resonance (SPR). The figure was created with Biorender.com.