Protein kinase C is crucial in signal transduction during IFN‐γ induction in endothelial cells

Abstract

We have demonstrated that IFN‐γ, a potent peptide mediator in inflammatory responses, operates via the protein kinase C dependent transduction pathway in the induction of class II MHC antigens on rat microvascular endothelial cells. Stimulators of protein kinase C, like PMA, replaced IFN‐γ in the induction of MHC class II on endothelial cells in a dose‐dependent manner. Selective enzyme inhibitors of protein kinase C, H‐7 as well as sphingosine down‐regulated the IFN‐γ induced class II expression in a dose‐dependent manner. Addition of cAMP or cGMP in the culture, had no effect on the class II expression on the endothelial cells. Transient rise of cytosolic Ca²⁺ by calcium ionophore A23187, or a calmodulin antagonist W‐7, had no effect on the IFN‐γ induced class II expression.