title: A vaccine prepared from a non-pathogenic H7N7 virus isolated from natural reservoir conferred protective immunity against the challenge with lethal dose of highly pathogenic avian influenza virus in chickens.
abstract: During 2001-2004, 41 H7 influenza viruses (2 H7N1 and 39 H7N7 strains) were isolated from fecal samples of migratory ducks that flew from Siberia in the autumn of each year to Japan and Mongolia. A phylogenetic analysis of the hemagglutinin (HA) genes of the nine representative isolates revealed that they belonged to the Eurasian lineage and the deduced amino acid sequence at the cleavage site of the HAs represented apathogenic profiles. One of the H7 isolates A/duck/Mongolia/736/02 (H7N7) was chosen from these H7 isolates for the preparation of the test vaccine. To improve the growth potential of A/duck/Mongolia/736/02 (H7N7) in chicken embryos, A/duck/Hokkaido/Vac-2/04 (H7N7) was generated by genetic reassortment between A/duck/Mongolia/736/02 (H7N7) as the donor of the PB2, PB1, PA, HA, NA, and NS genes and A/duck/Hokkaido/49/98 (H9N2) as that of NP and M genes. The test vaccine was prepared as follows; A/duck/Hokkaido/Vac-2/04 (H7N7) was propagated in chicken embryos and the virus in the allantoic fluid was inactivated and adjuvanted to form an oil-in-water emulsion. The test vaccine conferred immunity to chickens, completely protecting the manifestation of clinical signs against the challenge with lethal dose of H7 highly pathogenic avian influenza virus. These results indicate that influenza viruses isolated from natural reservoirs are useful for vaccine strains.
authors.affiliation: Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido 060-0818, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Sakabe
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sakoda
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Haraguchi
authors.forename: Norikazu
authors.initials: N
authors.lastname: Isoda
authors.forename: Kosuke
authors.initials: K
authors.lastname: Soda
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takakuwa
authors.forename: Kazue
authors.initials: K
authors.lastname: Saijo
authors.forename: Akira
authors.initials: A
authors.lastname: Sawata
authors.forename: Katsumi
authors.initials: K
authors.lastname: Kume
authors.forename: Junko
authors.initials: J
authors.lastname: Hagiwara
authors.forename: Kotaro
authors.initials: K
authors.lastname: Tuchiya
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Lin
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Sakamoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Imamura
authors.forename: Takashi
authors.initials: T
authors.lastname: Sasaki
authors.forename: Norihide
authors.initials: N
authors.lastname: Kokumai
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kawaoka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kida
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis / Q000096:biosynthesis; D000918:Antibody Specificity; D002645:Chickens; D003429:Cross Reactions; D004279:DNA, Viral / Q000235:genetics; D004196:Disease Outbreaks / Q000517:prevention & control; D004372:Ducks / Q000276:immunology / Q000821:virology*; D053126:Influenza A Virus, H7N7 Subtype / Q000276:immunology / Q000502:physiology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology; D005585:Influenza in Birds / Q000235:genetics / Q000276:immunology / Q000517:prevention & control*; D016865:Reassortant Viruses / Q000254:growth & development / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D004279:DNA, Viral; D007252:Influenza Vaccines