Evolutionary consequences of a decade of vaccination against subtype H6N2 influenza

Virology. 2016 Nov:498:226-239. doi: 10.1016/j.virol.2016.08.035. Epub 2016 Sep 15.

Abstract

The evolutionary dynamics of chicken-origin H6N2 viruses isolated in South Africa between 2002 and 2013 were investigated. Sub-lineages I and II continued to co-circulate under vaccination pressure, but sub-lineage I, from which the inactivated vaccine was derived, displayed a markedly higher mutation rate and a three-fold increase in the emergence of potential antigenic sites on the globular head of HA compared to sub-lineage II. Immunological pressure culminated in a critical phenotypic change as four of the five isolates from 2012 to 2013 had lost the ability to haemagglutinate chicken erythrocytes, correlating with a pattern of predicted O-glycosylation sites at residues 134, 137 and 141 within the critical 130 loop of the receptor binding domain site. Coassortment of the HA, NA and M genes in the respective sub-lineages contrasted reassortment of the other internal protein genes, and the vaccine seed strain itself was the probable donor of segments to sub-lineage II field strains.

Keywords: Avian influenza; Coassortment; Genetic drift; Glycosylation; H6N2; Reassortment; Vaccine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Viral
  • Antigens, Viral / genetics
  • Antigens, Viral / immunology
  • Antigens, Viral / metabolism
  • Chickens
  • Epitopes / genetics
  • Epitopes / immunology
  • Evolution, Molecular*
  • Genome, Viral
  • Genomics
  • Glycosylation
  • Hemagglutinin Glycoproteins, Influenza Virus / chemistry
  • Hemagglutinin Glycoproteins, Influenza Virus / genetics
  • Hemagglutinin Glycoproteins, Influenza Virus / immunology
  • Hemagglutinin Glycoproteins, Influenza Virus / metabolism
  • Immunization
  • Influenza A virus / classification*
  • Influenza A virus / genetics
  • Influenza A virus / immunology*
  • Influenza Vaccines / genetics
  • Influenza Vaccines / immunology*
  • Influenza in Birds / immunology*
  • Influenza in Birds / prevention & control*
  • Models, Molecular
  • Phenotype
  • Phylogeny
  • Protein Conformation
  • Reassortant Viruses / genetics
  • Reassortant Viruses / immunology
  • Selection, Genetic

Substances

  • Antibodies, Viral
  • Antigens, Viral
  • Epitopes
  • Hemagglutinin Glycoproteins, Influenza Virus
  • Influenza Vaccines