MULTIPLE PATHWAYS OF INTERFERON-INDUCED GENE-EXPRESSION IN MURINE MACROPHAGES

Steady-state levels of mRNAs that encode specific FcgammaR and la antigen genes have been measured in macrophages treated with interferons (IFNs) to examine the induction of these markers at the molecular level. Our previous studies suggested requirement for protein kinase C (PKC) in the IFN induction of these macrophage surface markers, although a difference in PKC dependence was found between IFN-alpha/beta- and IFN-gamma-induced FcgammaR expression. The protein kinase antagonist H7, used previously to distinguish between the surface induction of FcgammaR by IFN-alpha/beta and IFN-gamma, also distinguishes between the IFN-alpha and IFN-gamma in the induction of FCgammaRI mRNA and FcgammaRI surface expression' Protein kinase inhibitors blocked the IFN-gamma induction of la mRNA in a manner similar to that reported previously for cell surface la expression. It is concluded that FCgammaRI is induced by both IFN-alpha and IFN-gamma through distinct biochemical pathways, whereas IFN-gamma utilizes distinct pathways to induce the two macrophage activation markers, la antigen and FcgammaRI.