Fig. 1: Neutralizing activities of convalescent sera and monoclonal antibodies against SARS-CoV-2 variants.

a Infectivity of WT and variant pseudoviruses assessed in 293T-ACE2 and A549-ACE2 cells. Cells were inoculated with equivalent doses of each pseudotyped virus. WT, wild-type Spike (GenBank: QHD43416) pseudotyped virus; Variant 1, N501Y.V1 mutant Spike pseudotyped virus (containing the H60/V70 and Y144 deletions and N501Y, A570D, D614G, P681H, T716I, S982A, and D1118H mutations); Variant 2, N501Y.V2 mutant Spike pseudotyped virus (containing the K417N, E484K, N501Y, and D614G mutations). Neutralization of WT and variant pseudoviruses by convalescent sera. Pseudovirus-based neutralization assays were performed to detect neutralizing antibody (NAb) titers against SARS-CoV-2. The thresholds of detection were 1:40 of the ID₅₀. Twenty sera (indicated by circles) were drawn 5 to 33 days post symptom onset (b); 20 sera (indicated by triangles) were drawn ~8 months post symptom onset (c). The half-maximal inhibitory concentrations (IC₅₀) for tested monoclonal antibodies (mAbs) against pseudoviruses (d) and representative neutralization curves (e)