title: Genetic and antigenic characterization of H1 influenza viruses from United States swine from 2008.
abstract: Prior to the introduction of the 2009 pandemic H1N1 virus from humans into pigs, four phylogenetic clusters (α-, β-, γ- and δ) of the haemagglutinin (HA) gene from H1 influenza viruses could be found in US swine. Information regarding the antigenic relatedness of the H1 viruses was lacking due to the dynamic and variable nature of swine lineage H1. We characterized 12 H1 isolates from 2008 by using 454 genome-sequencing technology and phylogenetic analysis of all eight gene segments and by serological cross-reactivity in the haemagglutination inhibition (HI) assay. Genetic diversity was demonstrated in all gene segments, but most notably in the HA gene. The gene segments from the 2009 pandemic H1N1 formed clusters separate from North American swine lineage viruses, suggesting progenitors of the pandemic virus were not present in US pigs immediately prior to 2009. Serological cross-reactivity paired with antigenic cartography demonstrated that the viruses in the different phylogenetic clusters are also antigenically divergent.
authors.affiliation: Virus and Prion Disease Research Unit, USDA/ARS/NADC, Ames, IA, USA.
authors.forename: Alessio
authors.initials: A
authors.lastname: Lorusso
authors.forename: Amy L
authors.initials: AL
authors.lastname: Vincent
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Harland
authors.forename: David
authors.initials: D
authors.lastname: Alt
authors.forename: Darrell O
authors.initials: DO
authors.lastname: Bayles
authors.forename: Sabrina L
authors.initials: SL
authors.lastname: Swenson
authors.forename: Marie R
authors.initials: MR
authors.lastname: Gramer
authors.forename: Colin A
authors.initials: CA
authors.lastname: Russell
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Smith
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Lager
authors.forename: Nicola S
authors.initials: NS
authors.lastname: Lewis
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D014644:Genetic Variation; D005838:Genotype; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics* / Q000276:immunology*; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification* / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D057221:Influenza A Virus, H1N2 Subtype / Q000145:classification* / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D017422:Sequence Analysis, DNA; D012703:Serotyping; D013552:Swine / Q000821:virology*; D014481:United States
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D012367:RNA, Viral; C483468:hemagglutinin, human influenza A virus