Tropism of pandemic 2009 H1N1 influenza A virus

• Main Authors: Ririn eRamadhany, Mayo eYasugi, Shota eNakamura, Tomo eDaidoji, Yohei eWatanabe, Kazuo eTakahashi, Kazuyoshi eIkuta, Takaaki eNakaya
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2012-04-01
• Series: Frontiers in Microbiology
• Subjects: Influenza Virus; D222G; geentic diversity; H1N1pdm; next generation sequencer
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fmicb.2012.00128/full

Substitutions at the receptor binding site of the pandemic H1N1 2009 influenza A virus (H1N1pdm) hemagglutinin (HA) gene may be critical in determining whether a virus binds to human or avian receptors. Previous reports suggest that HA Gly222 and/or Arg223 allow viruses to bind preferentially to the 2,3-linked sialic acid found in avian species. We also demonstrated that serial passaging of influenza A virus in embryonated chicken eggs increased viral growth 32-64-fold, coincident with the increased prevalence of Gly222 or Arg223 in HA protein. In this study, we showed that the minor genotype of 2,3 linkage-tropic viruses in upper airways became dominant after passaging through chicken eggs. Viruses possessing HA containing N125D-Q223R, N125D-D187E-Q223R, K119N-D222G and K119N-N129S-D222G, were detected in both clinical specimens and egg-passaged samples. These results might suggest that egg-adapted viruses, likely represented by 2,3 linkage-tropic virus, were also present in human upper airways as a minor population and transmitted in humans during the outbreak of H1N1pdm.