FIG 3.

Receptor-binding specificity of avian influenza viruses. The data are presented as affinity constants of virus in complexes with sialyloligosaccharides (K_aff ± SD μM⁻¹ sialic acid). Viruses are grouped according to their subtypes and evolutionary relationships. The two circled LPAIVs were found to be exceptions as they revealed significantly higher binding affinities than other LPAIVs. Differences in the affinity constants (K_affs) between two groups of viruses, HPAIVs and LPAIVs, were statistically significant (P < 0.0001) and were determined using an unpaired two-tailed t test. See Fig. 2 for virus abbreviations.