title: Antigenic drift in H5N1 avian influenza virus in poultry is driven by mutations in major antigenic sites of the hemagglutinin molecule analogous to those for human influenza virus.
abstract: H5N1 highly pathogenic avian influenza virus has been endemic in poultry in Egypt since 2008, notwithstanding the implementation of mass vaccination and culling of infected birds. Extensive circulation of the virus has resulted in a progressive genetic evolution and an antigenic drift. In poultry, the occurrence of antigenic drift in avian influenza viruses is less well documented and the mechanisms remain to be clarified. To test the hypothesis that H5N1 antigenic drift is driven by mechanisms similar to type A influenza viruses in humans, we generated reassortant viruses, by reverse genetics, that harbored molecular changes identified in genetically divergent viruses circulating in the vaccinated population. Parental and reassortant phenotype viruses were antigenically analyzed by hemagglutination inhibition (HI) test and microneutralization (MN) assay. The results of the study indicate that the antigenic drift of H5N1 in poultry is driven by multiple mutations primarily occurring in major antigenic sites at the receptor binding subdomain, similarly to what has been described for human influenza H1 and H3 subtype viruses.
authors: OIE/FAO Reference Laboratory for Avian Influenza and Newcastle Disease, Istituto Zooprofilattico Sperimentale delle Venezie, 35020 Legnaro (PD), Italy. gcattoli@izsvenezie.it
authors: Giovanni
authors: G
authors: Cattoli
authors: Adelaide
authors: A
authors: Milani
authors: Nigel
authors: N
authors: Temperton
authors: Bianca
authors: B
authors: Zecchin
authors: Alessandra
authors: A
authors: Buratin
authors: Eleonora
authors: E
authors: Molesti
authors: Mona Meherez
authors: MM
authors: Aly
authors: Abdel
authors: A
authors: Arafa
authors: Ilaria
authors: I
authors: Capua
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology; D004534:Egypt; D006385:Hemagglutination Inhibition Tests; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification; D005585:Influenza in Birds / Q000276:immunology / Q000821:virology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D009500:Neutralization Tests; D011200:Poultry; D016865:Reassortant Viruses / Q000235:genetics / Q000276:immunology; D016415:Sequence Alignment
chemical_list: D000956:Antigens, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus