Suppressed induction of 2-5AS in cells with HTLV-I is not associated with the fluctuation of IFN-receptor, IFN-regulatory factors (IRF-1 and IRF-2) or STAT-1 alpha

Some viruses seem to be capable of suppressing interferon (IFN)-induced 2', 5'-oligoadenylate synthetase (2-5AS) induction. Cells infected with human T-lymphotropic virus type-I (HTLV-I) show different natures for the constitutive production of IFN-gamma or sensitivity to IFN, Poor induction of 2-5AS was found in IFN-gamma producer cells carrying HTLV-I (MT-1, MT-2 and SMT-1). On the other hand, in non- or low-producing cell lines of IFN-gamma such as HUT102 and OKM-2, significant activity of 2-5AS was induced by treatment with IFN-alpha. A satisfactory level of IFN receptor was detectable in SMT-1 cells in spite of the poor induction of 2-5AS, There were no differences in either the interferon regulatory factor-2 (IRF-2) mRNA transcript or the level of STAT-1 alpha between SMT-1 and HUT102 cells, However, the transcription of IRF-1 mRNA was slightly reduced in SMT-1 cells as compared with that of HUT102 cells.