Extended Data Fig. 3: Epitope characterization of mAbs.
a, Binding AUC of mAbs to indicated HAs. Each dot is one mAb. The dotted line indicates the threshold for positive binding. b, Percent binding of each mAb in each row to each indicated H5 TX/24 HA mutant relative to wildtype. To the right of the heatmap are nsEM of representative Fabs for each category in complex with HA. We were unable to obtain nsEM images from the Glyc90 sensitive group. The unclear mAbs had little to no reduction in binding to mutants. c, nsEM of Fabs in complex with HA of 7 of the 25 unclear mAbs demonstrating targeting to the RBS, lower lateral and base region. d,e, Fabs of base binding 310-2G04 were used in a competition ELISA with the remaining 18 unclear mAbs. In d is shown representative binding curves of 310-2G04 and upper lateral mAb 310-11F07 as a control with or without addition of 310-2G04 Fab. In e is indicated the fold change in binding AUC of each mAb with or without 310-2G04 Fab competition for binding. 310-2G04 Fab competed for binding to H5 TX/24 for 16 of the unclear mAbs indicating they bound the base region (left graph). Two mAbs did not have a large reduction in binding in the presence of 310-2G04 (right graph) and their epitope remained unclear. f, IGHV and IGK/LV gene usage of the upper lateral epitope targeting mAbs categorized as high neutralizers (black) or low neutralizers (gray).
