title: Improvement of influenza vaccine strain A/Vietnam/1194/2004 (H5N1) growth with the neuraminidase packaging sequence from A/Puerto Rico/8/34.
abstract: H5N1 influenza candidate vaccine viruses were developed using the "6+2" approach. The hemagglutinin (HA) and neuraminidase (NA) genes were derived from the popular H5N1 virus and the remaining six internal segments were derived from the A/Puerto Rico/8/34 strain (H1N1, PR8). However, some of these candidate strains have been reported to produce relatively low yields in vaccine manufacture. In this study, we found that the NA vRNA of the A/Vietnam/1194/2004 strain (H5N1, VN1194) was poorly packaged into recombinant viruses with a backbone of PR8 genes, which resulted in the formation of defective virions that did not include the NA vRNA in the genome. Using recombinant DNA techniques, we constructed a chimeric NA gene with the coding region of VN1194 NA flanked by the packaging signal sequence of the PR8 NA gene (41 bp form the 3' end of the vRNA and 67 bp from the 5' end). The packaging of the NA vRNA was restored to normal levels in the recombinant viruses containing the chimeric NA gene. Recombinant viruses containing the chimeric NA replicated much better in chicken embryonated eggs than viruses with the wild-type NA from VN1194. These findings suggest a novel strategy to improve in ovo growth of vaccine strains and to increase the number of vaccine doses available to save people if a pandemic were to occur.
authors.affiliation: State Key Laboratory of Respiratory Diseases, Institute of Respiratory Diseases, Guangzhou College of Medicine, Guangzhou, China.
authors.forename: Weiqi
authors.initials: W
authors.lastname: Pan
authors.forename: Zhenyuan
authors.initials: Z
authors.lastname: Dong
authors.forename: Weixu
authors.initials: W
authors.lastname: Meng
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Ting
authors.initials: T
authors.lastname: Li
authors.forename: Chufang
authors.initials: C
authors.lastname: Li
authors.forename: Beiwu
authors.initials: B
authors.lastname: Zhang
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
mesh_terms: D000818:Animals; D002460:Cell Line; D002642:Chick Embryo; D057809:HEK293 Cells; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000276:immunology; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics* / Q000254:growth & development* / Q000276:immunology; D007252:Influenza Vaccines / Q000235:genetics* / Q000276:immunology*; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control; D009439:Neuraminidase / Q000235:genetics* / Q000276:immunology; D012367:RNA, Viral / Q000235:genetics; D016865:Reassortant Viruses / Q000235:genetics / Q000276:immunology; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic / Q000276:immunology; D014764:Viral Proteins / Q000235:genetics* / Q000276:immunology; D019065:Virus Assembly; D014776:Virus Cultivation; D014779:Virus Replication
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D012367:RNA, Viral; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; D014764:Viral Proteins; C487630:NA protein, influenza A virus; D009439:Neuraminidase