title: Laboratory properties of cold-adapted influenza B live vaccine strains developed in the US and USSR, and their B/Ann Arbor/1/86 cold-adapted reassortant vaccine candidates.
abstract: The adaptation of two influenza B strains (B/Leningrad/14/55 and B/Ann Arbor/1/66) to replication at 25 degrees C is described. Comparison of the two viruses indicates that both also exhibit temperature sensitive phenotypes, although that of the virus B/Leningrad/14/55 is less pronounced. When inoculated into ferrets both viruses replicate well in the trachea, but only the B/Leningrad/14/55 cold-adapted virus replicates in the lungs. This virus exhibited a moderate level of attenuation in the animals, in contrast to the B/Ann Arbor/1/66 cold-adapted virus, which was fully attenuated. Reassortant viruses deriving the surface antigens of the contemporary wild type virus B/Ann Arbor/1/86 and most or all of their other genes, from one or other cold-adapted parent, were virtually indistinguishable from their respective cold-adapted parents. The B/Leningrad/14/55 reassortant was slightly more attenuated than its cold-adapted parent in ferrets. These studies extend knowledge of the properties of viruses used to prepare experimental live influenza B human vaccines.
authors.affiliation: Institute of Experimental Medicine, Academy of Medical Sciences, Leningrad, USSR.
authors.forename: G I
authors.initials: GI
authors.lastname: Alexandrova
authors.forename: H F
authors.initials: HF
authors.lastname: Maassab
authors.forename: A P
authors.initials: AP
authors.lastname: Kendal
authors.forename: T E
authors.initials: TE
authors.lastname: Medvedeva
authors.forename: A Y
authors.initials: AY
authors.lastname: Egorov
authors.forename: A I
authors.initials: AI
authors.lastname: Klimov
authors.forename: N J
authors.initials: NJ
authors.lastname: Cox
mesh_terms: D000818:Animals; D002642:Chick Embryo; D003080:Cold Temperature; D005289:Ferrets; D009981:Influenza B virus / Q000276:immunology / Q000502:physiology*; D007252:Influenza Vaccines; D010641:Phenotype; D014586:USSR; D014481:United States; D014613:Vaccines, Attenuated; D014779:Virus Replication
chemical_list: D007252:Influenza Vaccines; D014613:Vaccines, Attenuated