Molecular Analysis of the Induction of Class II Major Histocompatibility Antigen Expression on Murine Macrophages by Interferon-Gamma and Its Down-Regulation by Interferon-Alpha/Beta and Dexamethasone.

摘要

Previous studies have shown that the cell surface expression of class II major histocompatibility (MHC) antigens on murine macrophages (Ia antigens) is induced by interferon-gamma (IFN-gamma) and down-regulated by interferon-alpha/beta (IFN-alpha/beta) and dexamethasone (DEX). The studies described herein were performed in an attempt to examine the molecular mechanisms by which Ia antigens are induced on murine macrophages by recombinant IFN-gamma (riFN-gamma) and how this induction process is down-regulated by the selected inhibitors, IFN-alpha/beta and DEX. Steady-state analysis of total and cytoplasmic RNA revealed that riFN-gamma induced a 5.7- to 6.5-fold increase in levels of Ia (e.g., Aa-specific) mRNA. Increases in steady-state mRNA for Ab and Ea gene products were also observed in response to riFN-gamma. Maximum accumulation of Aa-specific mRNA occurred 24 hr post-treatment and required the continued presence of riFN-gamma. Induction of Aa-specific mRNA was sensitive to the protein synthesis inhibitor, cycloheximide (CHX).