Fig. 4
LAH epitope is exposed in post-fusion HA antigen. a HA-split antigen (X31) was converted into post-fusion form by treating at pH 5.0. Avidity index toward native and post-fusion HA antigens were determined from purified mAbs (LAH; 5 clones, CS; 5 clones, strain-specific; 4 clones) using strain-specific 1E11 clone as reference. Fold change was calculated by avidity index and comparably plotted from the three groups. Each dot represents the result from individual mAb clone. b Avidity index toward native and post-fusion HA antigens and fold change were plotted using the same supernatants from cross-reactive GC B cells in the lungs. c Cross-reactive and strain-specific GC B cells were gated, and the percentages of cells binding to native and post-fusion HA antigens that were labeled with fluorochromes were assessed by flow cytometry. Control histogram (gray filled); Narita HA-binding GC B cells of Narita virus-infected mice. d, e The percentages of strain-specific d and cross-reactive cells e binding to native and post-fusion HA antigens were plotted. Each circle represents the result from an individual mouse. The representative data from two independent experiments are shown. The P-values were determined with a two-tailed Mann–Whitney test (a, e) and Wilcoxon matched-pairs signed rank test b. *P < 0.05; **P < 0.01; ****P < 0.0001. Source data are provided as a Source Data file
