S Zou1, I Prud'homme, J M Weber. 1. Surveillance, Influenza and Viral Exanthemata, Laboratory Centre for Disease Control, Ottawa, Ontario.
Abstract
OBJECTIVE: To characterize the hemagglutinin (HA) gene of B/Canada/3/85, a prototype strain of influenza B virus variants that emerged in the 1984/85 influenza season and predominated in the 1985/86 season in Canada. DESIGN: Sequencing and comparison of the HA genes of B/Canada/3/85 and the vaccine strains for the 1985/86 season, B/USSR/100/83, and for the 1986/87 season, B/Ann Arbor/1/86. RESULTS: B/Canada/3/85 was similar to B/Ann Arbor/1/86 and significantly different from B/USSR/100/83. Phylogenetic analysis of the HA1-coding sequences indicated that B/Canada/3/85 and several other 1985 strains isolated in distant parts of the world were very closely related and were early variants representing the emergence of a new lineage, the B/Victoria/2/87 lineage. B/Canada/3/85 differed from B/USSR/100/83 in nucleotide sequence by 3.44% and in amino acid sequence by 3.33%. There was also an insertion of two amino acids in the HA1 region of B/Canada/3/85. CONCLUSIONS: B/Canada/3/85 was one of the herald strains for the 1985/1986 influenza B epidemic. The amino acid mutations and the two-codon insertion together may account for the observed antigenic changes in the HA of the influenza B variants.
OBJECTIVE: To characterize the hemagglutinin (HA) gene of B/Canada/3/85, a prototype strain of influenza B virus variants that emerged in the 1984/85 influenza season and predominated in the 1985/86 season in Canada. DESIGN: Sequencing and comparison of the HA genes of B/Canada/3/85 and the vaccine strains for the 1985/86 season, B/USSR/100/83, and for the 1986/87 season, B/Ann Arbor/1/86. RESULTS: B/Canada/3/85 was similar to B/Ann Arbor/1/86 and significantly different from B/USSR/100/83. Phylogenetic analysis of the HA1-coding sequences indicated that B/Canada/3/85 and several other 1985 strains isolated in distant parts of the world were very closely related and were early variants representing the emergence of a new lineage, the B/Victoria/2/87 lineage. B/Canada/3/85 differed from B/USSR/100/83 in nucleotide sequence by 3.44% and in amino acid sequence by 3.33%. There was also an insertion of two amino acids in the HA1 region of B/Canada/3/85. CONCLUSIONS: B/Canada/3/85 was one of the herald strains for the 1985/1986 influenza B epidemic. The amino acid mutations and the two-codon insertion together may account for the observed antigenic changes in the HA of the influenza B variants.
Entities:
Keywords:
Antigenic drift; Evolution; Hemagglutinin; Influenza B virus
Authors: G R Noble; H S Kaye; W B Yarbrough; B K Fiedler; C J Reed; M B Felker; A P Kendal; W R Dowdle Journal: J Infect Dis Date: 1977-12 Impact factor: 5.226