Activation of a suppressor T-cell pathway by interferon

Area of Science:

• Immunology
• Cell Biology
• Virology

Background:

• Murine fibroblast (type I) interferon (IFN-beta) exhibits antiviral activities and immune suppressive functions.
• IFN-beta's mechanism for suppressing antibody responses in murine spleen cells requires investigation.
• Previous studies indicate involvement of suppressor T cells and soluble mediators in immune suppression.

Purpose of the Study:

• To elucidate the mechanism by which IFN-beta suppresses antibody responses in murine spleen cells in vitro.
• To investigate the relationship between IFN-beta-induced suppression and known suppressor factors like SIRS/Mphi-SF.

Main Methods:

• Investigated the effect of catalase, 2-mercaptoethanol, and peroxidase substrates on IFN-beta-mediated suppression.
• Analyzed the properties of IFN-beta-induced suppressor T cells and their secreted factors (IFN-TsF).
• Compared the characteristics of IFN-TsF with soluble immune response suppressor (SIRS) and macrophage-derived suppressor factor (Mphi-SF).

Main Results:

• IFN-beta-mediated suppression was partially or completely blocked by catalase, 2-mercaptoethanol, and specific peroxidase substrates.
• IFN-beta treatment induced Lyt2+ suppressor T cells that produce a soluble factor (IFN-TsF).
• IFN-TsF shares kinetic patterns, molecular size, and susceptibility to inactivation with SIRS/Mphi-SF.

Conclusions:

• IFN-beta suppresses antibody responses by inducing suppressor T cells.
• The immunosuppressive mediators produced by IFN-beta-activated T cells are analogous to those in the SIRS/Mphi-SF pathway.
• IFN-beta's immunosuppressive effects are mediated, at least in part, through the activation of T cell-dependent suppressor pathways.