IFN-GAMMA INDUCES IL-12 MESSENGER-RNA EXPRESSION BY A MURINE MACROPHAGE CELL-LINE, J774

Interleukin (IL)-12 is a logical candidate for participation in the differentiation of T helper (Th) 1 cells. IL-12 is produced by macrophages and B cells and induces the production of interferon (IFN)-γ from Th1 cells and NK cells. In this study, we show that the IFN-γ itself is capable of inducing IL-12 mRNA expression in murine macrophage cell line J774. The mRNA was apparent by 12h after IFN-γ treatment, although maximal induction required 36 to 48h. Furthermore, we investigated the signal transduction mechanism responsible for the mRNA expression. The IFN-γ-inducible IL-12 mRNA was blocked by two protein tyrosin kinase (PTK) inhibitors, genistein and herbimycin A, suggesting that PTK is involved in the IFN-γ-inducible IL-12 mRNA expression. © 1994 Academic Press, Inc.