title: Evolutionary pattern of the hemagglutinin gene of influenza B viruses isolated in Japan: cocirculating lineages in the same epidemic season.
abstract: The unexpectedly low efficacy of influenza vaccine during school outbreaks of influenza B virus in the spring of 1987 in Japan was probably attributable to a poor antibody response of vaccinees to the epidemic viruses. An antigenic analysis of the causative B viruses isolated in 1987 and 1988 showed much variation in hemagglutination inhibition patterns. The nucleotide sequences that code for the HA1 domain of B/Fukuoka/c-27/81, B/Ibaraki/2/85, B/Nagasaki/1/87, and B/Yamagata/16/88 viruses were determined and compared with those of the previously reported hemagglutinin genes. The nucleotide sequences of the hemagglutinin gene of a new variant, B/Yamagata/16/88, had only 93.4% homology with those of two other viruses from the same epidemic. An analysis of nucleotide and amino acid substitutions of the hemagglutinin genes of influenza B viruses revealed that new and some old variants could cocirculate in the same epidemic. A phylogenetic tree constructed by the neighbor-joining method allowed estimation of an evolutionary rate of 2.3 x 10(-3) synonymous (silent) substitutions per nucleotide site per year in the hemagglutinin gene.
authors.affiliation: Department of Virology and Rickettsiology, National Institute of Health, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kanegae
authors.forename: S
authors.initials: S
authors.lastname: Sugita
authors.forename: A
authors.initials: A
authors.lastname: Endo
authors.forename: M
authors.initials: M
authors.lastname: Ishida
authors.forename: S
authors.initials: S
authors.lastname: Senya
authors.forename: K
authors.initials: K
authors.lastname: Osako
authors.forename: K
authors.initials: K
authors.lastname: Nerome
authors.forename: A
authors.initials: A
authors.lastname: Oya
mesh_terms: D000293:Adolescent; D000595:Amino Acid Sequence; D000914:Antibodies, Viral / Q000032:analysis; D001483:Base Sequence; D005075:Biological Evolution; D005814:Genes, Viral; D006389:Hemagglutinins, Viral / Q000235:genetics*; D006801:Humans; D009981:Influenza B virus / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D007251:Influenza, Human / Q000453:epidemiology; D007564:Japan; D008969:Molecular Sequence Data; D009154:Mutation; D015345:Oligonucleotide Probes; D012689:Sequence Homology, Nucleic Acid
chemical_list: D000914:Antibodies, Viral; D006389:Hemagglutinins, Viral; D015345:Oligonucleotide Probes