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

Abstract

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.