Fig. 3: Anti-RBD-binding antibodies and neutralizing activity against ancestral and VOCs-derived spike.

a, ELISA showing SARS-CoV-2 S-RBD^WT, -RBD^D and -RBD^O IgG titers in V_NLRs, V_NHRs and V_R subjects in plasma at T0, 3M and 6M. ELISA results shown as ETs based on a standard. The dotted lines represent the LOD. At T0: V_NLRs (n = 30), V_NHRs (n = 30), V_R subjects (n = 26); 3M: V_NLRs (n = 28), V_NHRs (n = 27), V_R subjects (n = 25); 6M: V_NLRs (n = 30), V_NHRs (n = 29), V_R subjects (n = 26). b, Neutralization assay showing 50%neutralizing dose titers (ND₅₀) against S-RBD^WT, -RBD^D and -RBD^O measured by pseudovirus (PSV)-neutralizing assay in plasma from V_NLRs (n = 20) and V_NHRs (n = 20) at month 6. c, Spearman’s correlation plots showing PSV ND₅₀ and IgG ELISA ETs against S-RBD^WT, -RBD^D and -RBD^O in plasma from V_NLRs (n = 20) and V_NHRs (n = 20) at month 6. V_NLRs, RBD^WT: R = 0.721 and P < 0.001, RBD^D: R = 0.2305 and P = NS, RBD^O: P = NS; V_NHRs, RBD^WT: R = 0.2168 and P = NS, RBD^D: R = 0.6282 and P < 0.01, RBD^O: R = 0.4277 and P < 0.01. NA indicates no neutralizing activity. The same subjects were longitudinally analyzed. The box plots indicate median, IQR and minimum/maximum. Each dot of box plots represents the average across two (a) and three (b) technical replicates of the same subject; the data are pooled from multiple experiments. Statistics were calculated using two-sided Wilcoxon’s signed-rank and two-sided Wilcoxon’s rank-sum test. ^**P < 0.01; ^***P < 0.001; ^****P < 0.0001.