Fig. 4: XBB reinfection elicits cross-neutralizing antibodies among Omicron variants including JN.1 and XEC.
a–i Serum samples collected at T1 and T3 from individuals with single infection (a, c, e, g) and double infection (b, d, f, h, i) were absorbed with empty beads (No Dp) or beads coated with RBD proteins of WT, BA.5 or XBB variants, and then used for pseudovirus neutralization assays. Neutralization assays were performed at a starting dilution of 1:100 due to the limited samples available. Only samples with positive values (pVNT50 > 100) for each variant were considered for cross-reactivity testing, and the number of samples (n) used in the assay is indicated at the top. The neutralization titer in RBD-absorbed samples was compared with the titer in no Dp samples. Dashed lines indicate the limit of detection (pVNT50 = 100); GMTs are labeled as black lines and shown above each column, with fold-changes and significance compared with the no Dp control shown at the top (left panels). The percentages of variant-specific neutralizing antibodies were compared for samples between T1 and T3 (means of each column are labeled as black lines with the number shown at the top), with pie charts illustrating the proportion of variant-specific and cross-reactive neutralizing antibodies in each group (middle and right panels). j Correlation of BA.5-specific neutralization antibody titer that did not cross-react with WT at T1 with the proportion of XBB.1.5 neutralization antibody that did not cross-react with WT at T3. Spearman correlation test was performed. k Neutralization potency of BA.5 and XBB antibodies before and after depletion of antibodies that cross-react with WT at T3 in the double infection group. Means of each column are labeled as black lines and shown at the top, with fold-changes and significance compared with the no Dp control shown at the top. *P < 0.05, **P < 0.01, ***P < 0.001; ns, not significant.
