Toscana virus induces interferon although its NSs protein reveals antagonistic activity

J Gen Virol. 2011 Jan;92(Pt 1):71-9. doi: 10.1099/vir.0.025999-0. Epub 2010 Sep 22.


Toscana virus (TOSV) is a phlebotomus-transmitted virus that belongs to the family Bunyaviridae and causes widespread infections in humans; about 30 % of these cases result in aseptic meningitis. In the present study, it was shown that TOSV is an inducer of beta interferon (IFN-β), although its non-structural protein (NSs) could inhibit the induction of IFN-β if expressed in a heterologous context. A recombinant Rift Valley fever virus expressing the TOSV NSs could suppress IFN-β expression in infected cells. Moreover, in cells expressing NSs protein from a cDNA plasmid, IFN-β transcripts were not inducible by poly(I : C). Unlike other members of the family Bunyaviridae, TOSV appears to express an NSs protein that is a weak antagonist of IFN induction. Characterization of the interaction of TOSV with the IFN system will help our understanding of virus-host cell interactions and may explain why the pathogenesis of this disease is mostly mild in humans.

MeSH terms

  • Animals
  • Cell Line
  • Genetic Vectors
  • Humans
  • Interferon-beta / antagonists & inhibitors*
  • Interferon-beta / biosynthesis*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology
  • Rift Valley fever virus / genetics
  • Sandfly fever Naples virus / immunology*
  • Viral Nonstructural Proteins / genetics
  • Viral Nonstructural Proteins / immunology*


  • Recombinant Proteins
  • Viral Nonstructural Proteins
  • Interferon-beta