Overexpression of chicken interferon regulatory factor-1 (Ch-IRF-1) induces constitutive expression of MHC class I antigens but does not confer virusresistance to a permanent chicken fibroblast cell line

The chicken fibroblast cell line C32 has been transfected with the chicken homolog (Ch-IRF-1) of the mammalian transcription factor IRF-1. Stable tran sfectants were generated, constitutively overexpressing Ch-IRF-1 mRNA and p rotein. Cells overexpressing Ch-IRF-1 showed enhanced constitutive expressi on of MHC class I (B-F, beta-microglobulin) antigens. With increasing numbe r of passages cells with normal B-F IV surface antigen expression accumulat ed. In the revertants, the amount of Ch-IRF-1 mRNA was reduced. Overexpress ion of Ch-IRF-1 had no effect on the constitutive expression and the induct ion by chicken interferon type-I and type-II (Ch-IFN) of guanylate-binding protein (GBP). Susceptibility to vesicular stomatitis virus, sindbis virus, Newcastle disease virus and vaccinia virus was not altered by overexpressi on of Ch-IRF-1. An antiviral state could be induced against all viruses tes ted by similar amounts of Ch-IFN type I in clone 20-18 expressing Ch-IRF-1 and cells transfected with empty vector. (C) 1998 Elsevier Science B.V. All rights reserved.