Fig. 2.

Receptor binding specificity of the reference viruses in this study. Virus binding assays of the reference viruses to sialylglycopolymers containing either α2,3 Sia (blue circle) or α2,6 Sia (red triangle). (A) Human H1N1 strain. (B) Human H3N2 strain. (C and D) Bird H5N1 strains. (E and F) H5N1 mutant strains with increased α2,6 Sia binding affinity and residual α2,3 Sia binding. Each data point is the mean±SD of three independent experiments. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)