Fig. 4

Canyon and 2- and 3-fold plateau-specific neutralizing antibodies. a Canyon-specific antibodies exhibit more potent neutralizing activities than 2- and 3-fold plateau-specific antibodies. The difference in the neutralization concentrations between two groups (7 or 8 canyon-specific representative mAbs vs. four plateau-specific representative mAbs) was examined by the Mann–Whitney test. The data are shown as box and whisker plots of the neutralizing activities (μg ml⁻¹) of canyon mAbs (gray dots box) and plateau mAbs (empty box), with the median values shown as middle bars and mean values shown as plus signs. The neutralizing activity of each representative mAb is defined as the lowest concentration that completely inhibited CPE formation. Each antibody was assayed in triplicate for each virus, and the assay was carried out twice with equivalent results. b The average heavy-chain CDR3 length of the canyon-specific antibodies (n = 11) is significantly longer than that of the 2- and 3-fold plateau-specific antibodies (n = 27) (Mann–Whitney test) (Table 1). The data are shown as box and whisker plots, with median values shown as middle bars and mean values shown as plus signs. NT neutralization