Edible bird's nest: N- and O-glycan analysis and synergistic anti-avian influenza virus activity with neuraminidase inhibitors.

Zoonotic avian influenza viruses have continued to infect people on occasion. During treatment, antiviral resistant viruses have occasionally emerged, highlighting the need for a novel strategy for treating human illness. After pancreatin treatment, edible bird's nest (EBN), swiftlet saliva consumed for health purposes, possesses anti-avian viral activity by inhibiting receptor-binding hemagglutinin (HA) activity. Glycan analysis revealed an abundance of α2,3Neu5Ac decoy receptors in pancreatin-treated EBN. Fucosylated tri-α2,3Neu5Ac tri-antennary N-glycans (N-35) and di-α2,3Neu5Ac core 2 O-glycans (O-15) are predominant, accounting for 53.46% and 44.66% of total N- and O-glycan amounts, respectively. Isobologram analysis revealed that the treated EBN had a strong synergistic effect with either oseltamivir carboxylate or zanamivir, a competitive inhibitor of receptor-destroying neuraminidases (NAs), against the avian H5N1 virus. Taken together, EBN has the potential to be developed as a food-derived avian viral trap to prevent and decrease avian virus infection as well as in combination with a viral releasing-NA inhibitor to increase therapeutic potency, reduce toxicity, delay resistance development, and potentially prevent pandemic onset.