Fig. 1

Generation of mAbs against the S2 subunit of SARS-CoV-2 S protein. A Schematic illustration of the immunization procedure. BALB/c mice were immunized by I.M. of 10 µg of mRNA-LNP encoding the Beta variant S protein every 2 weeks. A final booster of 25 µg trimeric Beta variant S protein was administered by I.P. on the seventh week. B Serum samples were harvested at week 6 and analyzed for antibody response to S protein. The immunosorbent assay indicated the antibody levels of post-immunized samples (red line) with serial dilutions compared with pre-immunized serum samples (black line). C The binding activities of fourteen serially diluted mAbs were detected by immunosorbent assay; plates were coated with recombinant full-length S protein (Beta strain), S1 (Wuhan strain), S2 (Wuhan strain) or RBD (Beta strain). Normal mouse IgG (NMIgG) was used as a negative control. B-RBD-mAb was used as a positive control for RBD and S1 subunit of SARS-CoV-2.