P cell stimulating factor and glucocorticoids oppose the action of interferon-γ in inducing Ia antigens on T-dependent mast cells (P cells)

Abstract

The expression of Ia antigens of cultured lines of T-dependent mast cells (TDMC) or persisting (P) cells was modulated by three hormones: interferon-γ (IFN-γ), P cell-stimulating factor (PF), and glucocorticoids. The induction of Ia antigens by cloned IFN-γ was inhibited by a homogeneous preparation of PSF, the T cell-derived factor that TDMC require for their in vitro growth. This inhibitory effect of PSF was dose-dependent and could not be overcome by increasing the levels of IFN-γ. Other cytokines such as granulocyte/macrophage colony-stimulating factor, T cell growth factor, and L cell-derived macrophage colony-stimulating factor had no inhibitory effect. Thus, two different T cell lymph..