title: The genes associated with trans-dominance of the influenza A cold-adapted live virus vaccine.
abstract: Segment 7 (M) of the cold-adapted live influenza A virus vaccine plays a primary role in the ability of this virus to interfere with the replication of wild-type influenza A viruses. This conclusion is based on several lines of evidence. Single gene reassortant viruses derived by crossing influenza A/Ann Arbor/6/60 (H2N2) cold-adapted donor virus with an epidemic wild-type strain, A/Korea/1/82 (H3N2), were tested for their ability to interfere with wild-type parental virus in the Madin-Darby line of canine kidney cells and embryonated eggs. It was apparent in both hosts that the single gene reassortant carrying segment 7 (M) derived from the cold-adapted virus was dominant over wild-type virus. Additional confirmation of the role of segment 7 (M) in trans-dominance of the cold-adapted vaccine virus was derived from the analysis of reassortants produced by mixed infection by a wild-type virus and its cold-adapted reassortant vaccine strain. After three serial passages, the virus yield contained a high proportion of reassortants carrying segment 7 (M) of the cold-adapted parental strain. When used in mixed infections, these reassortants were dominant over the replication of the parental wild-type virus.
authors.affiliation: Department of Molecular Genetics and Biochemistry, School of Medicine, University of Pittsburgh, PA 15261.
authors.forename: P
authors.initials: P
authors.lastname: Whitaker-Dowling
authors.forename: R
authors.initials: R
authors.lastname: Zvolenski
authors.forename: J S
authors.initials: JS
authors.lastname: Youngner
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D005814:Genes, Viral; D009980:Influenza A virus / Q000235:genetics* / Q000254:growth & development; D010641:Phenotype; D012692:Serial Passage; D013696:Temperature; D014613:Vaccines, Attenuated; D014762:Viral Interference; D014764:Viral Proteins / Q000235:genetics; D014765:Viral Vaccines; D014779:Virus Replication / Q000235:genetics
chemical_list: D014613:Vaccines, Attenuated; D014764:Viral Proteins; D014765:Viral Vaccines