Fig. 3.

(A) Neutralizing activity of mAbs (S-9-11 and N-176-15) was further confirmed by pseudovirus infection assay. ‘+’: no Ab, ‘−’: no pseudovirus infection. The dilution of the mAb ascites and antiserum is 1:100 and 1:1000. ‘S’: S-9-11 ascites, ‘N’: N-176-15 ascites, ‘U’: an unrelated mAb ascites (anti mouse CD4). Infectivity: ‘+’ is calculated as 100% and ‘−’ as zero. (B) A denatured antigen ELISA used to determine whether the epitope is linear or conformational. RBD-Fc denatured by heat or SDS/β-mercaptoethanol was coated on 96-well micro-plates. ‘S’: mAb S-9-11, ‘N’: mAb N-176-15. ‘+’: RBD-Fc without denaturation. ‘Control’: an unrelated mAb.