The expression of sialylated high-antennary N-glycans in edible bird’s nest

Edible bird’s nest (EBN) is the nest made from the saliva of Collocalia swift. Recently, we have found that EBN extract could strongly inhibit infection of influenza viruses in a host-range-independent manner [Guo, C. T.; Takahashi, T.; Bukawa, W.; Takahashi, N.; Yagi, H.; Kato, K.; Hidari, K. I.; Miyamoto, D.; Suzuki, T.; Suzuki, Y. Antiviral Res. 2006, 70, 140–146]. Although this antiviral activity might be attributed to O- or N-glycoconjugates, no N-glycan structures have so far been described for EBN. Here, we report the N-glycosylation profile of EBN, in which a tri-antennary N-glycan bearing the α2,3-N-acetylneuraminic acid residues is displayed as a major component. We suggest that the sialylated high-antennary N-glycans of EBN contribute to the inhibition of influenza viral infection.