FIG 11.

Antigenic sites in HA trimers of H1N1/SC1918 and H3N2/Aic68. HA1s and HA2s in HA trimers are white and brown, respectively. (Left) Antigenic sites Sa (blue), Sb (cyan), Ca1 (orange), Ca2 (green), and Cb (violet) in two of three HAs from H1N1/SC1918 are indicated in colors, and a region corresponding to site R is red. (Right) Antigenic sites A (blue), B (cyan), C (yellow), D in the left side of HA (orange), D in the right side of HA (green), and E (violet) in two of three HAs from H3N2/Aic68 are colored as indicated, and sites L and R are red.