Altered #receptor-binding #specificity of #gull-adapted #H13 avian #influenza viruses corresponds to their unique host preferences
Highlights • H13 HAs exhibit binding specificity for fucosylate α2-3 sialosides. • The 130-loop and K227 are critical for H13 HA binding specificity. • Fucosylated α2-3 sialosides are widely distributed in slaty-backed gulls. Abstract Avian influenza viruses (AIVs) recognize α2-3 sialosides as receptors . Previous studies showed that the structural diversity within α2-3 sialosides is related to the host specificity of AIVs. H13 AIVs are primarily isolated from gulls , although almost all AIV subtypes have been isolated from ducks , the natural hosts of AIVs. To elucidate the molecular basis of the host specificity of H13 viruses to gulls, the receptor-binding specificity of H13 hemagglutinins (HAs) and the distribution of viral receptors in gulls were investigated. The results revealed that recombinant HA (rHA) of H13 viruses had a binding preference for fucosylated α2-3 sialosides, which were distributed widely in the respiratory tract and intestines of gulls but not ...