Influenza A viruses can bind sialic acid-terminating glycan receptors, and species specificity is often correlated with sialic acid linkage with avian strains recognizing α2,3-linked sialylated glycans and mammalian strains preferring α2,6-linked sialylated glycans. These paradigms derive primarily from studies involving erythrocyte agglutination, binding to synthetic receptor analogs or binding to undefined surface markers on cells or tissues. Here, we present the first examination of the N-glycome of the human lung for identifying natural receptors for a range of avian and mammalian influenza viruses. We found that the human lung contains many α2,3- and α2,6-linked sialylated glycan determinants bound by virus, but all viruses also bound to phosphorylated, nonsialylated glycans.
