Interferon-γ, but Not Interleukin-4, Suppresses Experimental Polymyositis.

Objective: C protein-induced myositis (CIM) is a mouse model of polymyositis in which activated antigen-specific CD8+ T cells injure the muscles. Animal models of autoimmunity that have been examined in the past for the effects of the type 1 cytokine interferon-γ (IFNγ) and the type 2 cytokine interleukin-4 (IL-4) are all mediated by pathogenic CD4+ T cells. In those models, the disruption of IFNγ leads to up-regulation of IL-17A, exacerbating the disease with neutrophil infiltration into sites of inflammation.