Molecular Characterisation of the Haemagglutinin Glycan-Binding Specificity of Egg-Adapted Vaccine Strains of the Pandemic 2009 H1N1 Swine Influenza A Virus.

ABSTRACT: The haemagglutinin (HA) glycan binding selectivity of H1N1 influenza viruses is an important determinant for the host range of the virus and egg-adaption during vaccine production. This study integrates glycan binding data with structure-recognition models to examine the impact of the K123N, D225G and Q226R mutations (as seen in the HA of vaccine strains of the pandemic 2009 H1N1 swine influenza A virus). The glycan-binding selectivity of three A/California/07/09 vaccine production strains, and purified recombinant A/California/07/09 HAs harboring these mutations was examined via a solid-phase ELISA assay. Wild-type A/California/07/09 recombinant HA bound specifically to ?2,6-linked sialyl-glycans, with no affinity for the ?2,3-linked sialyl-glycans in the array. In contrast, the vaccine virus strains and recombinant HA harboring the Q226R HA mutation displayed a comparable pattern of highly specific binding to ?2,3-linked sialyl-glycans, with a negligible affinity for ?2,6-linked sialyl-glycans. The D225G A/California/07/09 recombinant HA displayed an enhanced binding affinity for both ?2,6- and ?2,3-linked sialyl-glycans in the array. Notably its ?2,6-glycan affinity was generally higher compared to its ?2,3-glycan affinity, which may explain why the double mutant was not naturally selected during egg-adaption of the virus. The K123N mutation which introduces a glycosylation site proximal to the receptor binding site, did not impact the ?2,3/?2,6 glycan selectivity, however, it lowered the overall glycan binding affinity of the HA; suggesting glycosylation may interfere with receptor binding. Docking models and 'per residues' scoring were employed to provide a structure-recognition rational for the experimental glycan binding data. Collectively, the glycan binding data inform future vaccine design strategies to introduce the D225G or Q226R amino acid substitutions into recombinant H1N1 viruses.

SUBMITTER: Carbone V 

PROVIDER: S-EPMC6272818 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature