Preferential Recognition of Avian-Like Receptors in Human Influenza A H7N9 Viruses

See allHide authors and affiliations

Science  06 Dec 2013:
Vol. 342, Issue 6163, pp. 1230-1235
DOI: 10.1126/science.1243761

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution

Avian Affinity for H7N9

Structural analyses of the binding of avian origin H7N9 influenza viruses have revealed how the receptor-binding characteristics differentiate between birds and mammals, and studies involving the use of whole viruses have suggested that the virus is acquiring human-type receptor specificity. In contrast, Xu et al. (p. 1230) show that the H7 hemagglutinin strongly retains its specificity for avian-type receptors by using cocrystal structures with receptor analogs and glycan binding analysis with recombinant hemagglutinin against a library of receptor analogs. Thus, current human H7N9 viruses appear to remain poorly adapted to human receptors, and additional mutations will be required to achieve specificity for human-type receptors equivalent to those of human pandemic viruses.


The 2013 outbreak of avian-origin H7N9 influenza in eastern China has raised concerns about its ability to transmit in the human population. The hemagglutinin glycoprotein of most human H7N9 viruses carries Leu226, a residue linked to adaptation of H2N2 and H3N2 pandemic viruses to human receptors. However, glycan array analysis of the H7 hemagglutinin reveals negligible binding to humanlike α2-6–linked receptors and strong preference for a subset of avian-like α2-3–linked glycans recognized by all avian H7 viruses. Crystal structures of H7N9 hemagglutinin and six hemagglutinin-glycan complexes have elucidated the structural basis for preferential recognition of avian-like receptors. These findings suggest that the current human H7N9 viruses are poorly adapted for efficient human-to-human transmission.

View Full Text

Stay Connected to Science