The neutralizing activity of the convalescents' sera to authentic SARS-CoV-2 viruses
(A) The neutralizing activity of 30 representative sera against authentic SARS-CoV-2 WT strain at 20- and 100-fold dilution. The sera were grouped based on their neutralizing activity to WT-D614G pseudovirus.
(B and C) The neutralizing activity of serum group 1 (B) and serum group 2 (C) against the indicated authentic SARS-CoV-2 viruses. SARS-CoV-2 N protein (red) in the infected cells was detected through immunofluorescence assay at 24 h post-infection. The nucleus was stained blue. Scale bar, 200 μm. The serum sample numbers are indicated above the pictures.