Comparative analyses of the antiviral activities of IgG and IgA antibodies to influenza A virus M2 protein

Kosuke Okuya, Nao Eguchi, Rashid Manzoor, Reiko Yoshida, Shinji Saito, Tadaki Suzuki, Michihito Sasaki, Takeshi Saito, Yurie Kida, Akina Mori-Kajihara, Hiroko Miyamoto, Osamu Ichii, Masahiro Kajihara, Hideaki Higashi, Ayato Takada

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Abstract: The influenza A virus (IAV) matrix-2 (M2) protein is an antigenically conserved viral envelope protein that plays an important role in virus budding together with another envelope protein, hemagglutinin (HA). An M2-specific mouse monoclonal IgG antibody, rM2ss23, which binds to the ectodomain of the M2 protein, has been shown to be a non-neutralizing antibody, but inhibits plaque formation of IAV strains. In this study, we generated chimeric rM2ss23 (ch-rM2ss23) IgG and IgA antibodies with the same variable region and compared their antiviral activities. Using gel chromatography, ch-rM2ss23 IgA were divided into three antibody subsets: monomeric IgA (m-IgA), dimeric IgA (d-IgA), and trimeric and tetrameric IgA (t/q-IgA). We found that t/q-IgA had a significantly higher capacity to reduce the plaque size of IAVs than IgG and m-IgA, most likely due to the decreased number of progeny virus particles produced from infected cells. Interestingly, HA-M2 colocalization was remarkably reduced on the infected cell surface in the presence of ch-rM2ss23 antibodies. These results indicate that anti-M2 polymeric IgA restricts IAV budding more efficiently than IgG and suggest a role of anti-M2 IgA in cross-protective immunity to IAVs.

Original languageEnglish (US)
Article number780
Issue number7
StatePublished - Jul 2020
Externally publishedYes


  • Antibody
  • Budding inhibition
  • Cross-protective
  • IgA
  • Influenza A virus
  • Matrix 2 protein

ASJC Scopus subject areas

  • Infectious Diseases
  • Virology


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