title: Genetic and phenotypic analysis of reassortants of high growth and low growth strains of influenza B virus.
abstract: The yield of influenza virus in eggs is critical to influenza vaccine production and availability, but the contribution of specific genes to the growth properties of influenza B viruses is not well understood. Influenza B/Beijing/184/93 and B/Shangdong/7/97 were chosen for study because B/Shangdong/7/97 replicated to several fold higher titers in eggs than B/Beijing/184/93 as demonstrated by hemagglutination titers and EID50. A reassortant with the HA, NP and PB2 genes from B/Beijing/184/93 and all other genes from B/Shangdong/7/97 had the high growth phenotype of B/Shangdong/7/97 in eggs, which suggests that NS, M, NA, PB1 or PA, or a combination of these genes derived from B/Shangdong/7/97 were needed for the high growth phenotype of the reassortants. A high degree of homology was found among the genetic sequences of B/Beijing/184/93, B/Shangdong/7/97, and other influenza B viruses. However, differences potentially related to growth characteristics were suggested by analysis of the deduced amino acid (AA) sequences of four genes: NS (NS1, NS2), M (BM2), NA (NA, NB) and PB1. The studies identify multiple genes that may affect growth of influenza B viruses in eggs.
authors.affiliation: Laboratory of Pediatric and Respiratory Viral Diseases, Division of Viral Products, Office of Vaccines Research and Review, Center for Biologics and Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA. vodeiko@cber.fda.gov
authors.forename: G M
authors.initials: GM
authors.lastname: Vodeiko
authors.forename: J
authors.initials: J
authors.lastname: McInnis
authors.forename: V
authors.initials: V
authors.lastname: Chizhikov
authors.forename: R A
authors.initials: RA
authors.lastname: Levandowski
mesh_terms: D000818:Animals; D002460:Cell Line; D002642:Chick Embryo; D004279:DNA, Viral / Q000032:analysis / Q000096:biosynthesis; D005838:Genotype; D006387:Hemagglutination, Viral; D009981:Influenza B virus / Q000235:genetics* / Q000254:growth & development*; D007252:Influenza Vaccines / Q000276:immunology; D007700:Kinetics; D009439:Neuraminidase / Q000032:analysis / Q000378:metabolism; D010641:Phenotype; D012367:RNA, Viral / Q000032:analysis / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013045:Species Specificity
chemical_list: D004279:DNA, Viral; D007252:Influenza Vaccines; D012367:RNA, Viral; D009439:Neuraminidase