title: Serologic and genetic characterization of North American H3N2 swine influenza A viruses.
abstract: The H3N2 subtype of influenza A viruses isolated from pigs in the United States and Canada has shown both genetic and antigenic diversity. The objective of this study was to determine the serologic and genetic characteristics of contemporary strains of these viruses. Genetic analysis of 18 reference strains and 8 selected strains demonstrated differences in 1% to 9% of the nucleotides of the hemagglutinin (HA) gene. Phylogenetic analysis of the HA gene revealed 3 genetic clusters, as well as divergence of cluster III viruses from a cluster III prototype virus (A/Swine/Illinois/21587/99). By means of 1-way cross-hemagglutination inhibition with antiserum against 5 field isolates and 3 vaccine viruses, most of 97 isolates tested could be placed in 1 of 3 serogroups. The several isolates that did not react with any antiserum were in genetic cluster III, which suggests that continuous antigenic drift in cluster III may have resulted in virus variants. The efficacy of commercial vaccines against these virus variants should be evaluated with vaccination and challenge studies.
authors: Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, 1333 Gortner Avenue, St. Paul, Minnesota 55108, USA. grame003@umn.edu
authors: Marie René
authors: MR
authors: Gramer
authors: Jee Hoon
authors: JH
authors: Lee
authors: Young Ki
authors: YK
authors: Choi
authors: Sagar M
authors: SM
authors: Goyal
authors: Han Soo
authors: HS
authors: Joo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000940:Antigenic Variation; D001483:Base Sequence; D016000:Cluster Analysis; D003429:Cross Reactions; D014644:Genetic Variation; D006385:Hemagglutination Inhibition Tests; D053122:Influenza A Virus, H3N2 Subtype / Q000145:classification* / Q000235:genetics*; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D016415:Sequence Alignment; D012703:Serotyping / Q000662:veterinary; D013552:Swine; D013553:Swine Diseases / Q000821:virology*
chemical_list: D012367:RNA, Viral
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