title: Immune escape mutants of Highly Pathogenic Avian Influenza H5N1 selected using polyclonal sera: identification of key amino acids in the HA protein.
abstract: Evolution of Avian Influenza (AI) viruses--especially of the Highly Pathogenic Avian Influenza (HPAI) H5N1 subtype--is a major issue for the poultry industry. HPAI H5N1 epidemics are associated with huge economic losses and are sometimes connected to human morbidity and mortality. Vaccination (either as a preventive measure or as a means to control outbreaks) is an approach that splits the scientific community, due to the risk of it being a potential driving force in HPAI evolution through the selection of mutants able to escape vaccination-induced immunity. It is therefore essential to study how mutations are selected due to immune pressure. To this effect, we performed an in vitro selection of mutants from HPAI A/turkey/Turkey/1/05 (H5N1), using immune pressure from homologous polyclonal sera. After 42 rounds of selection, we identified 5 amino acid substitutions in the Haemagglutinin (HA) protein, most of which were located in areas of antigenic importance and suspected to be prone to selection pressure. We report that most of the mutations took place early in the selection process. Finally, our antigenic cartography studies showed that the antigenic distance between the selected isolates and their parent strain increased with passage number.
authors.affiliation: Quantitative Veterinary Epidemiology, Department of Animal Sciences, Wageningen University, Wageningen, The Netherlands ; Department of Virology, Central Veterinary Institute of Wageningen University and Research Centre, Lelystad, The Netherlands.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Sitaras
authors.affiliation: Institute of Diagnostic Virology, Friedrich-Loeffler Institut, Greifswald-Insel Riems, Germany.
authors.forename: Donata
authors.initials: D
authors.lastname: Kalthoff
authors.affiliation: Institute of Diagnostic Virology, Friedrich-Loeffler Institut, Greifswald-Insel Riems, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Beer
authors.affiliation: Department of Virology, Central Veterinary Institute of Wageningen University and Research Centre, Lelystad, The Netherlands.
authors.forename: Ben
authors.initials: B
authors.lastname: Peeters
authors.affiliation: Quantitative Veterinary Epidemiology, Department of Animal Sciences, Wageningen University, Wageningen, The Netherlands.
authors.forename: Mart C M
authors.initials: MC
authors.lastname: de Jong
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics / Q000276:immunology; D000596:Amino Acids / Q000235:genetics* / Q000276:immunology; D000818:Animals; D001717:Birds / Q000276:immunology / Q000821:virology; D004196:Disease Outbreaks; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics* / Q000276:immunology; D007106:Immune Sera / Q000276:immunology*; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics* / Q000276:immunology*; D005585:Influenza in Birds / Q000276:immunology*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics* / Q000276:immunology; D014611:Vaccination / Q000379:methods
chemical_list: D000596:Amino Acids; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007106:Immune Sera