Fig. 7: Interaction analysis and mutagenesis for the epitope of 12H5.
a Amino acid substitutions found in the HA of C12H5-induced escape mutants with four influenza A strains. b Reactivity profiles of CA HA and its mutants against C12H5 antibodies measured through sandwich ELISA. The EC50 values were calculated by sigmoid fitting, as shown in Supplementary Fig. 11. EC50 values are plotted as circles along the horizontal axis for each protein. c Binding affinity measurements for HA and its mutants against C12H5, as determined with SPR. The kinetic constants between C12H5 and Y98A, A137E, H141A, A142E, G143R, A144E, W153A, and D190A mutants were not determinable. The calculated affinity constants and fitting results are shown in Supplementary Table 8 and Fig. 11. The EC50 and KD values in b and c are averaged data from two independent experiments. d Comparison of binding reactivity of five variant sites with the mutants and wild type of QH/2005 HA in two experiments. ND, not detectable. e Comparison of binding reactivity of 12H5 to the 190 mutants and wild type of CA4/2009 and QH/2005 HA from two experiments. f Blocking assay by human sera (n = 5) of H1N1 infection (H1N1-RNA positive) to antibodies binding. Two groups were compared with the control group using a paired two-tailed t-test. NS means not statistically significant. g ELISA assay to analysis the sensitivity of human sera (n = 5) of H1N1 infection to the critical point mutations for C12H5 recognition. Statistical analyses were performed using one-way ANOVA with Dunn’s multiple comparisons test (*P < 0.05, **P < 0.01 and ****P < 0.0001). h, i Critical residues of 12H5 on HA of H1N1 and H5N1 viruses; the outlined black region shows all epitopes of 12H5; the same amino acid types are indicated with red lines. Data in b–e are presented as mean values, data in f, g are presented as mean values ± SD. Source data are provided as a Source Data file.
