Cell-cell fusion induced by measles virus amplifies the type I interferon response.

Florence Herschke (1) , Sébastien Plumet (1) , Thomas Duhen (2) , Olga Azocar (2, 3) , Johan Druelle (4) , David Laine (2) , Timothy Fabian Wild (4) , Chantal Rabourdin-Combe (2) , Denis Gerlier (1) , Hélène Valentin (2)

1 VirPath - Virologie et Pathologie Humaine
2 Immunobiologie fondamentale et clinique
3 BLG - BioSciences Lyon-Gerland
4 Virologie humaine

Measles virus (MeV) infection is characterized by the formation of multinuclear giant cells (MGC). We report that beta interferon (IFN-beta) production is amplified in vitro by the formation of virus-induced MGC derived from human epithelial cells or mature conventional dendritic cells. Both fusion and IFN-beta response amplification were inhibited in a dose-dependent way by a fusion-inhibitory peptide after MeV infection of epithelial cells. This effect was observed at both low and high multiplicities of infection. While in the absence of virus replication, the cell-cell fusion mediated by MeV H/F glycoproteins did not activate any IFN-alpha/beta production, an amplified IFN-beta response was observed when H/F-induced MGC were infected with a nonfusogenic recombinant chimerical virus. Time lapse microscopy studies revealed that MeV-infected MGC from epithelial cells have a highly dynamic behavior and an unexpected long life span. Following cell-cell fusion, both of the RIG-I and IFN-beta gene deficiencies were trans complemented to induce IFN-beta production. Production of IFN-beta and IFN-alpha was also observed in MeV-infected immature dendritic cells (iDC) and mature dendritic cells (mDC). In contrast to iDC, MeV infection of mDC induced MGC, which produced enhanced amounts of IFN-alpha/beta. The amplification of IFN-beta production was associated with a sustained nuclear localization of IFN regulatory factor 3 (IRF-3) in MeV-induced MGC derived from both epithelial cells and mDC, while the IRF-7 up-regulation was poorly sensitive to the fusion process. Therefore, MeV-induced cell-cell fusion amplifies IFN-alpha/beta production in infected cells, and this indicates that MGC contribute to the antiviral immune response.

Mots clés: measles virus; interferon; fusion; dendritic cells; epithelial cells

Domaines: Virologie

Florence Herschke, Sébastien Plumet, Thomas Duhen, Olga Azocar, Johan Druelle, et al.. Cell-cell fusion induced by measles virus amplifies the type I interferon response.. Journal of Virology, 2007, 81 (23), pp.12859-71. ⟨10.1128/JVI.00078-07⟩. ⟨hal-00169132⟩