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. 2007 Jul;71(3):201-6.

Serologic and genetic characterization of North American H3N2 swine influenza A viruses

Marie René Gramer  1 , Jee Hoon Lee, Young Ki Choi, Sagar M Goyal, Han Soo Joo
Affiliations

Serologic and genetic characterization of North American H3N2 swine influenza A viruses

Marie René Gramer et al. Can J Vet Res. 2007 Jul.

Abstract
in English, French

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.

Le sous-type H3N2 du virus de l’influenza A isolé de porcs aux États-Unis et au Canada montre une diversité génétique et antigénique. Les objectifs de la présente étude étaient de déterminer les caractéristiques sérologiques et génétiques de souches contemporaines de ces virus. Une analyse génétique de 18 souches de référence et de 8 souches sélectionnées a démontré des différences variant de 1 % à 9 % des nucléotides du gène de l’hémagglutinine (HA). Une analyse phylogénétique du gène HA a révélé 3 regroupements génétiques, de même qu’une divergence de virus du regroupement III du prototype du regroupement III (A/Swine/Illinois/21587/99). À l’aide d’une épreuve d’inhibition de l’hémagglutination croisée unidirectionnelle, utilisant des antisérums dirigés contre 5 isolats de champs et 3 souches vaccinales, la plupart des 97 isolats testés ont pu être classés dans 1 des 3 sérogroupes. Les isolats qui n’ont pas réagi avec aucun antisérum se retrouvaient dans le regroupement III, ce qui suggère qu’une dérive antigénique continue dans le regroupement III pourrait avoir entraîné l’apparition de variants. L’efficacité des vaccins commerciaux envers ces virus variants devrait être évaluée par des études de vaccination et d’infections défis.

(Traduit par Docteur Serge Messier)

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Figures

Figure 1
Figure 1
Phylogenetic tree of the hemagglutinin (HA) genes of selected H3N2 influenza A viruses, constructed in Megalign (DNAStar, Madison, Wisconsin, USA). The length of each pair of branches represents the distance between sequence pairs. The units 0 to 6.5 at the bottom of the tree indicate the number of nucleotide substitutions. The 5 isolates used to prepare antiserum for the study were classified as follows: A and D, cluster I (A/Swine/Texas/4199-2/98-like); B and C, cluster III (A/Swine/ Illinois/21587/99-like); and E, cluster II (A/Swine/Colorado/23619/ 99-like). TX — Texas; MO — Missouri; MN — Minnesota; NC — North Carolina; OK — Oklahoma; IL — Illinois; CO — Colorado; ON — Ontario; NE — Nebraska; IA — Iowa.
Figure 2
Figure 2
Phylogenetic tree of HA gene nucleotide sequences of 5 nonreactive H3N2 viruses (starred) and 8 H3N2 viruses in GenBank. WI — Wisconsin.
Figure 3
Figure 3
Phylogenetic tree of HA nucleotide sequences of the 5 non-reactive H3N2 viruses (starred), 7 H3N2 viruses in GenBank (italicized and bolded), and 34 contemporary H3N2 viruses from the MVDL database. BC — British Columbia; MB — Manitoba; QC — Quebec; AB — Alberta; SC — South Carolina.
See this image and copyright information in PMC

References

    1. Webby RJ, Swenson SL, Krauss SL, Gerrish PJ, Goyal SM, Webster RG. Evolution of swine H3N2 influenza viruses in the United States. J Virol. 2000;74:8243–8251. - PMC - PubMed
    1. Karasin AI, Olsen CW, Anderson GA. Genetic characterization of an H1N2 influenza virus isolated from a pig in Indiana. J Clin Microbiol. 2000;38:2453–2456. - PMC - PubMed
    1. Karasin AI, Landgraf J, Swenson S, et al. Genetic characterization of H1N2 influenza A viruses isolated from pigs throughout the United States. J Clin Microbiol. 2002;40:1073–1079. - PMC - PubMed
    1. Olsen CW, Carey S, Hinshaw L, Karasin AI. Virologic and serologic surveillance for human, swine and avian influenza virus infections among pigs in the north-central United States. Arch Virol. 2000;145:1399–1419. - PMC - PubMed
    1. Olsen CW. The emergence of novel swine influenza viruses in North America. Virus Res. 2002;85:199–210. - PubMed

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