Fig. 5: The S protein directed antibody responses shifted from RBD to NTD.

a Anti-S1 domain, S2 domain, N-terminal domain (NTD), Receptor binding domain (RBD) and RBD-Omicron (RBD-O) antibodies were measured by ELISA at 3rd 2 wks, 3rd 26 wks or 4th 2 wks. b–d Antibody titers for each protein were compared between 3rd 2 wks and 26 wks, 4th 2 wks and 3rd 26 wks, 4th 2 wks and 3rd 2 wks, respectively. Percentage of participants with increased titers (former/later >1, orange), decreased titers (former/later <1, blue) or unchanged titers (former/later =1, green) were shown. e Anti-S1 (blue circle) and anti-S2 (orange triangle) antibody titers at each time point were compared. f Anti-RBD (blue circle) and anti-NTD (orange triangle) antibody titers at each time point were compared. g Antibody titers for RBD-Omicron. The orange dashed line represents the kinetics of the geometric mean titer of anti-RBD IgG. h The fold change of NTD- or RBD-binding IgG between 3rd 2 wks and 4th 2 wks were compared. i NAbs against Omicron BA.2 variants were measured by pseudovirus-based neutralization assays. j The fold change of NAbs against BA.1 or BA.2 from 3rd 2 wks to 4th 2 wks were compared. For (e–j), n = 38 biologically independent samples. Data were shown as Geometric mean ± 95% Cl in (e–g, i) or as box and whiskers in (h, j), indicating median (middle line), 25th, 75th percentile (box) and 5th and 95th percentile (whiskers). Two-tailed Friedman test followed by Dunn’s multiple comparisons test was used for (e–g), and two-tailed Wilcoxon matched-pairs signed rank test was used for (h–j). ns, not significant. Source data are provided as a Source Data file.