title: Effect of D222G mutation in the hemagglutinin protein on receptor binding, pathogenesis and transmissibility of the 2009 pandemic H1N1 influenza virus.
abstract: Influenza viruses isolated during the 2009 H1N1 pandemic generally lack known molecular determinants of virulence associated with previous pandemic and highly pathogenic avian influenza viruses. The frequency of the amino acid substitution D222G in the hemagglutinin (HA) of 2009 H1N1 viruses isolated from severe but not mild human cases represents the first molecular marker associated with enhanced disease. To assess the relative contribution of this substitution in virus pathogenesis, transmission, and tropism, we introduced D222G by reverse genetics in the wild-type HA of the 2009 H1N1 virus, A/California/04/09 (CA/04). A dose-dependent glycan array analysis with the D222G virus showed a modest reduction in the binding avidity to human-like (α2-6 sialylated glycan) receptors and an increase in the binding to avian-like (α2-3 sialylated glycan) receptors in comparison with wild-type virus. In the ferret pathogenesis model, the D222G mutant virus was found to be similar to wild-type CA/04 virus with respect to lethargy, weight loss and replication efficiency in the upper and lower respiratory tract. Moreover, based on viral detection, the respiratory droplet transmission properties of these two viruses were found to be similar. The D222G virus failed to productively infect mice inoculated by the ocular route, but exhibited greater viral replication and weight loss than wild-type CA/04 virus in mice inoculated by the intranasal route. In a more relevant human cell model, D222G virus replicated with delayed kinetics compared with wild-type virus but to higher titer in human bronchial epithelial cells. These findings suggest that although the D222G mutation does not influence virus transmission, it may be considered a molecular marker for enhanced replication in certain cell types.
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Belser
authors.forename: Akila
authors.initials: A
authors.lastname: Jayaraman
authors.forename: Rahul
authors.initials: R
authors.lastname: Raman
authors.forename: Claudia
authors.initials: C
authors.lastname: Pappas
authors.forename: Hui
authors.initials: H
authors.lastname: Zeng
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Cox
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Katz
authors.forename: Ram
authors.initials: R
authors.lastname: Sasisekharan
authors.forename: Terrence M
authors.initials: TM
authors.lastname: Tumpey
mesh_terms: D000818:Animals; D002460:Cell Line; D005260:Female; D005289:Ferrets; D006388:Hemagglutinins / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D007251:Influenza, Human / Q000635:transmission / Q000821:virology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation
chemical_list: D006388:Hemagglutinins