A single amino acid change in hemagglutinin reduces the cross-reactivity of antiserum against an equine influenza vaccine strain

Arch Virol. 2019 Sep;164(9):2355-2358. doi: 10.1007/s00705-019-04328-4. Epub 2019 Jun 21.


Equine influenza virus is an important pathogen for the horse industry because of its economic impact, and vaccination is a key control measure. Our previous work suggested that a mutation at position 144 in the hemagglutinin of Florida sublineage clade 2 viruses reduces the cross-neutralizing activity of antiserum against a former vaccine strain. To confirm this suggestion, here, we generated viruses by reverse genetics. Antibody titers against the mutated viruses were one-tenth to one-sixteenth of those against the former vaccine strain. Our findings confirm that this single amino acid substitution reduces the cross-reactivity of antiserum against this former Japanese vaccine.

MeSH terms

  • Amino Acid Substitution
  • Animals
  • Antibodies, Viral / immunology*
  • Cross Reactions
  • Hemagglutinin Glycoproteins, Influenza Virus / administration & dosage
  • Hemagglutinin Glycoproteins, Influenza Virus / chemistry
  • Hemagglutinin Glycoproteins, Influenza Virus / genetics*
  • Hemagglutinin Glycoproteins, Influenza Virus / immunology*
  • Horse Diseases / immunology*
  • Horse Diseases / virology
  • Horses
  • Immune Sera / immunology
  • Influenza A virus / genetics
  • Influenza A virus / immunology*
  • Influenza Vaccines / administration & dosage
  • Influenza Vaccines / chemistry
  • Influenza Vaccines / genetics*
  • Influenza Vaccines / immunology*
  • Orthomyxoviridae Infections / immunology
  • Orthomyxoviridae Infections / veterinary*
  • Orthomyxoviridae Infections / virology


  • Antibodies, Viral
  • Hemagglutinin Glycoproteins, Influenza Virus
  • Immune Sera
  • Influenza Vaccines