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Genetic analysis of an influenza B virus isolated from a patient with encephalopathy in Japan *
Author(s) -
Shiraishi Kyoko,
Lindstrom Stephen E.,
Saito Takehiko,
Shinjoh Masayoshi,
Nerome Reiko,
Funatsumaru Sadayuki,
Nerome Kuniaki
Publication year - 2001
Publication title -
journal of medical virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 121
eISSN - 1096-9071
pISSN - 0146-6615
DOI - 10.1002/jmv.2077
Subject(s) - virology , neuraminidase , biology , virus , hemagglutinin (influenza) , h5n1 genetic structure , gene , amino acid , japanese encephalitis , encephalitis , nucleoprotein , viral matrix protein , phylogenetic tree , genetics , medicine , infectious disease (medical specialty) , disease , covid-19 , pathology
An influenza B virus, B/Saga/S172/99 (SAG99), was isolated from the nasopharynx of a patient with encephalopathy/encephalitis in Japan in 1999. To clarify the molecular characteristics of this virus, detailed analysis of the gene segments coding for the hemagglutinin (HA), neuraminidase (NA), nucleoprotein (NP), matrix protein (M) and non‐structural protein (NS) was undertaken. All five genes of SAG99 showed high nucleotide and predicted amino acid similarities with those of recent non‐encephalopathic strains isolated in the same epidemic season. Subsequent phylogenetic analysis revealed that all five gene segments of SAG99 analyzed in the present study were most similar to those of the recent Yamagata/16/88‐like viruses. The hemagglutinin and neuraminidase proteins of SAG99 were each distinguished from those of recent epidemic strains by one characteristic amino acid substitution. These substitutions were not found in the previously reported encephalopathy/encephalitis‐derived influenza B viruses, and we could not find any common characteristic amino acid changes in SAG99 and these viruses. Similarly, among the internal proteins studied, only the M2 protein of SAG99 was found to contain a single novel amino acid change when compared with other recent isolates. Thus, it was apparent that SAG99 contained very few amino acid differences when compared with other epidemic viruses. The association of recent B/Yamagata/16/88‐like viruses with encephalitis/encephalopathy observed in the present study and previously suggest that these viruses may have a higher potential for causing neurological complications in certain individuals. J. Med. Virol. 65:590–597, 2001. © 2001 Wiley‐Liss, Inc.