title: High genetic and antigenic similarity between a swine H3N2 influenza A virus and a prior human influenza vaccine virus: a possible immune pressure-driven cross-species transmission.
abstract: In late April of 2009, a global outbreak of human influenza was reported. The causative agent is a highly unusual reassortant H1N1 influenza virus carrying genetic segments derived from swine, human and avian influenza viruses. In this study, we compared the HA, NA and other gene segments of a swine H3N2 influenza A virus, A/Swine/Guangdong/z5/2003, which was isolated from pigs in 2003 in Guangdong Province, China, to the predominant human and swine H3N2 viruses. We found that the similarity of gene segments of A/Swine/Guangdong/z5/2003 was closer to Moscow/99-like human H3N2 virus than Europe swine H3N2 viruses during 1999-2002. These results suggest that A/Swine/Guangdong/z5/2003 may be porcine in origin, possibly being driven by human immune pressure induced by either natural H3N2 virus infection or use of A/Moscow/10/99 (H3N2)-based human influenza vaccine. The results further confirm that swine may play a dual role as a "shelter" for hosting influenza virus from humans or birds and as a "mixing vessel" for generating reassortant influenza viruses, such as the one causing current influenza pandemic.
authors.affiliation: Lindsley F. Kimball Research Institute, The New York Blood Center, New York, NY 10065, USA.
authors.forename: Chungen
authors.initials: C
authors.lastname: Pan
authors.forename: Guiping
authors.initials: G
authors.lastname: Wang
authors.forename: Ming
authors.initials: M
authors.lastname: Liao
authors.forename: Gui-Hong
authors.initials: GH
authors.lastname: Zhang
authors.forename: Shibo
authors.initials: S
authors.lastname: Jiang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype / Q000145:classification* / Q000235:genetics / Q000276:immunology; D007252:Influenza Vaccines / Q000145:classification* / Q000235:genetics / Q000276:immunology; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology / Q000635:transmission*; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000276:immunology / Q000635:transmission*; D010802:Phylogeny; D016865:Reassortant Viruses / Q000145:classification* / Q000235:genetics / Q000276:immunology; D013552:Swine / Q000276:immunology / Q000821:virology*
chemical_list: D000956:Antigens, Viral; D007252:Influenza Vaccines