INVESTIGATION OF IFN TYPE-I RECEPTOR AND IFN REGULATORY FACTOR EXPRESSION RELATING TO INDUCTION OF 2',5'-OLIGOADENYLATE SYNTHETASE IN CELLSPERSISTENTLY INFECTED WITH THE MUMPS-VIRUS

Poor induction of interferon-induced 2', 5'-oligoadenylate synthetase (2-5AS) activity has been demonstrated in cells persistently infected with the mumps virus or human T-lymphotropic virus type-I (HTLV-I). Th e suppression of 2-5AS induction is the result of the repression of 2- 5AS gene expression at the transcription level. In a general way, afte r the binding of interferon-alpha (IFN-alpha) to cell surface-specific receptors, expression of 2-5AS gene is thought to be regulated by som e transacting factors, IFN-regulatory factors (IRF-1 and IRF-2) and th e IFN-stimulated gene factor (ISGF-3, a complex consisting of STAT-1 a lpha, STAT-2 and p48). To clarify the cause of the suppression mechani sm(s), fluctuation in the number of IFN receptors and the levels of mR NAs in both IRF-1 and IRF-2 were examined in cells persistently infect ed with the mumps virus (FLMT and KBMT). There were few defferences in the number of IFN receptors and the level of IRF-2 mRNA between persi stently infected cells and uninfected control cells. After the treatme nt of cells with IFN, a slight reduction of IRF-1 mRNA was found in pe rsistently infected cells as compared with that of the uninfected cont rol cells.