title: Key molecular factors in hemagglutinin and PB2 contribute to efficient transmission of the 2009 H1N1 pandemic influenza virus.
abstract: Animal influenza viruses pose a clear threat to public health. Transmissibility among humans is a prerequisite for a novel influenza virus to cause a human pandemic. A novel reassortant swine influenza virus acquired sustained human-to-human transmissibility and caused the 2009 influenza pandemic. However, the molecular aspects of influenza virus transmission remain poorly understood. Here, we show that an amino acid in hemagglutinin (HA) is important for the 2009 H1N1 influenza pandemic virus (2009/H1N1) to bind to human virus receptors and confer respiratory droplet transmissibility in mammals. We found that the change from glutamine (Q) to arginine (R) at position 226 of HA, which causes a switch in receptor-binding preference from human α-2,6 to avian α-2,3 sialic acid, resulted in a virus incapable of respiratory droplet transmission in guinea pigs and reduced the virus's ability to replicate in the lungs of ferrets. The change from alanine (A) to threonine (T) at position 271 of PB2 also abolished the virus's respiratory droplet transmission in guinea pigs, and this mutation, together with the HA Q226R mutation, abolished the virus's respiratory droplet transmission in ferrets. Furthermore, we found that amino acid 271A of PB2 plays a key role in virus acquisition of the mutation at position 226 of HA that confers human receptor recognition. Our results highlight the importance of both the PB2 and HA genes on the adaptation and transmission of influenza viruses in humans and provide important insights for monitoring and evaluating the pandemic potential of field influenza viruses.
authors: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China.
authors: Ying
authors: Y
authors: Zhang
authors: Qianyi
authors: Q
authors: Zhang
authors: Yuwei
authors: Y
authors: Gao
authors: Xijun
authors: X
authors: He
authors: Huihui
authors: H
authors: Kong
authors: Yongping
authors: Y
authors: Jiang
authors: Yuntao
authors: Y
authors: Guan
authors: Xianzhu
authors: X
authors: Xia
authors: Yuelong
authors: Y
authors: Shu
authors: Yoshihiro
authors: Y
authors: Kawaoka
authors: Zhigao
authors: Z
authors: Bu
authors: Hualan
authors: H
authors: Chen
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D006224:Cricetinae; D004195:Disease Models, Animal; D005260:Female; D005289:Ferrets; D005814:Genes, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000502:physiology*; D054884:Host-Pathogen Interactions / Q000235:genetics / Q000502:physiology; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D007251:Influenza, Human / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D008168:Lung / Q000473:pathology / Q000821:virology; D009976:Orthomyxoviridae Infections / Q000473:pathology / Q000635:transmission / Q000821:virology; D058873:Pandemics; D011134:Polysaccharides / Q000378:metabolism; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics / Q000502:physiology*; D011991:Receptors, Virus / Q000502:physiology; D013552:Swine; D014764:Viral Proteins / Q000235:genetics / Q000502:physiology*; D014774:Virulence / Q000235:genetics / Q000502:physiology; D014779:Virus Replication / Q000235:genetics / Q000502:physiology
chemical_list: C543345:H1N1 virus hemagglutinin; D019267:Hemagglutinin Glycoproteins, Influenza Virus; C057027:PB2 protein, Influenzavirus A; D011134:Polysaccharides; D011991:Receptors, Virus; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase