Stimulation of natural interferon-alpha/beta-producing cells by Staphylococcus aureus

J Interferon Cytokine Res. 1996 Jan;16(1):7-16. doi: 10.1089/jir.1996.16.7.


Human peripheral blood mononuclear cells (PBMCs) produced high levels of antiviral activity, as determined by bioassay, when stimulated by Staphylococcus aureus Cowan I (SAC) and E. coli. Specific immunoassays demonstrated the presence of both IFN-alpha and gamma and, for SAC, also low levels of IFN-beta. The frequencies of SAC-induced IF N-alpha-producing cells (IPCs) were up to 1-2 per 10(3) PBMCs. These IPCs expressed the HLA-DR and CD4 antigens but not CD3, CD14, or CD19, thus resembling the natural IFN-alpha-producing cells (NIPC). The SAC was more efficient as IFN inducer when heat killed than when streptomycin inhibited. The SAC was inhibitory to virally induced IFN-alpha responses, in particular when streptomycin inhibited. Both pronase treatment and mechanical disruption of SAC cells abolished their capacity to induce IFN-alpha production. Staphylococcal strains lacking or expressing low levels of protein A (SpA) showed a decreased ability to induce IFN-alpha production. However, purified SpA did not itself induce IFN-alpha. Possibly, SpA together with other bacterial surface proteins is important for the capacity of SAC to induce IFN-alpha production in NIPC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Division / drug effects
  • Humans
  • Immunophenotyping
  • In Vitro Techniques
  • Interferon Inducers*
  • Interferon-alpha / biosynthesis*
  • Interferon-beta / biosynthesis*
  • Kinetics
  • Leukocytes, Mononuclear / metabolism*
  • Staphylococcal Protein A / pharmacology*
  • Staphylococcus aureus / drug effects*
  • Streptomycin / pharmacology
  • Stress, Mechanical


  • Interferon Inducers
  • Interferon-alpha
  • Staphylococcal Protein A
  • Interferon-beta
  • Streptomycin