Evolutionary characteristics of influenza B virus since its first isolation in 1940: dynamic circulation of deletion and insertion mechanism

Abstract

New antigenic variants of B/Yamagata/16/88-like lineage which appeared in the season of 1997 as a minor strain tended to predominate in the following season. Also, we could observe for the first time, three peaks of activity caused by H3N2 virus and two variants of B influenza virus. Antigenic and phylogenetic analyses revealed that B/Victoria/2/87-like variants appeared again in Japan in 1997 after a nine-year absence. Influenza B viruses evolved into three major lineages, including the earliest strain (I), B/Yamagata/16/88-like variants (II), which comprised of three sublineages (II-(i), II-(ii), II-(iii)), and B/Victoria/2/87-like variants (III). Evolution of influenza B virus hemagglutinin was apparently distinguishable from that of influenza A virus, showing a systematic mechanism of nucleotide deletion and insertion. This phenomenon was observed to be closely related to evolutionary pathways of I, II-(i), II-(ii), II-(iii) and III lineages. It was noteworthy to reveal that the nucleotide deletion and insertion mechanism of influenza B virus completed one cycle over a fifty-year period, and that a three nucleotide deletion was again observed in 1997 strains belonging to lineage II-(iii). It was evident that amino acid substitutions accompanying nucleotide insertions were highly conserved.

Multiple Genotypes of Influenza B Virus Circulated between 1979 and 2003

“…on May 7, 2018 by guest http://jvi.asm.org/ 20,22,24,25,33). This is the first report that considers the viral genome as a whole and examines the relationships between strains based on comparisons of all eight gene segments.…”

Rescue of influenza B virus from eight plasmids

“…Influenza B viruses segregate between two distinct lineages, B͞Victoria͞2͞87-like viruses and B͞Yamagata͞16͞88-like viruses (2)(3)(4)(5)(6). To demonstrate the utility of B͞Yamanashi͞ 166͞98 (a B͞Yamagata͞16͞88-like virus) to efficiently express antigens from both these lineages, reassortants containing PB1, PB2, PA, NP, M, NS from B͞Yamanashi͞166͞98, and the HA and NA from strains representing both the Victoria and Yamagata lineages (6 ϩ 2 reassortants) were generated.…”

“…Antigenic drift is caused by amino acid changes in HA and NA, which are caused by nucleotide misincorporation during viral replication. In addition, insertion and͞or deletion of nucleotides in the HA and NA gene segments of influenza B viruses have been shown to be a source of antigenic diversity and evolution (5,6). Although it is well established that influenza B viruses can evolve by reassortment (6,7), little is known about the animal reservoir for this virus.…”

Molekulare Analyse humaner Influenzaviren

“…Zur Entstehung dieser beiden Linien hat eine Reihe von Insertions-und Deletionsereignissen beigetragen, die vor allem den Bereich der Aminosäureregion 159-168 des HA-Gens betreffen. Deletionen an den Positionen 162 und 164 sind charakteristisch für Vertreter der Yamagata-Linie der frühen 1990er-Jahre, während jüngere Yamagata-like-Viren nur noch eine Deletion an Position 162 aufweisen [28]. Insertionen haben zum Entstehen der Victoria-Linie geführt.…”