Attenuation of an influenza A virus due to alteration of its hemagglutinin-neuraminidase functional balance in mice

Fumihiro Gen, Shinya Yamada, Kentaro Kato, Hiroomi Akashi, Yoshihiro Kawaoka, Taisuke Horimoto

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

Influenza A viruses possess two surface glycoproteins, hemagglutinin (HA), which binds to sialic-acid-containing receptors, and neuraminidase (NA), which removes sialic acid from host cells. It is well established that the HA-NA functional balance regulates the efficiency of virus replication. Here, we selected a plaque variant of the WSN (H1N1) strain that grew better than the wild-type virus in NA-expressing MDCK cell culture. A reverse genetics study revealed that the single mutation HA E190K, which occurs infrequently in naturally isolated H1N1 viruses, was responsible for the phenotype of this variant. Receptor assays indicated that this mutation did not affect the receptor specificity of HA but enhanced its receptor-binding affinity, resulting in altered HA-NA functional balance relative to that of the wild-type virus. We also found that this variant replicated in nasal turbinates at an equivalent level but in lungs at a lower level compared with wild-type virus, demonstrating its attenuation in mice. Together, our data demonstrated the importance of the HA-NA functional balance for influenza virus replication in an in vivo biological setting.

Original languageEnglish
Pages (from-to)1003-1011
Number of pages9
JournalArchives of virology
Volume158
Issue number5
DOIs
Publication statusPublished - 2013
Externally publishedYes

ASJC Scopus subject areas

  • Virology

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