Suppression of Interferon-induced Oligo-2\u27, 5\u27-adenylate Synthetase Induction in Human Hepatoma Cell Line, Li-7

Induction of oligo-2\u27, 5\u27-adenylate synthetase (2-5AS) activity by interferon (IFN) was investigated in a human hepatoma cell line, Li-7 cells. Little induction of 2-5AS activity by IFN was demonstrated in Li-7 cells in comparison with other types of cell lines including Ramos, NC-37, FL, Co-3. Furthermore, failure to induce 2-5AS was much clearer in old-cultured cells. Cell growth inhibition by IFN was demonstrated in only high titers of IFN (>10? IU/ml), in which the enzyme had one hundred fold higher activity than that of untreated cells. Poor induction of 2-5AS was in part the result of some inhibitor presented in cellular extracts of Li-7 cells and the decreased level of 2-5AS mRNA transcription

Effect of Interferon on Cells Persistently Infected with Human T Cell Leukemia Virus (HTLV-I)

Spontaneous production of interferon-gamma (IFN- γ) was shown in four (MT-1, MT-2, SMT-1 and HUT 102) of five human T-lymphoblastoid cell lines persistently infected with human T cell leukemea virus type I (MT-1, MT-2, SMT-1, HUT 102 and OKM-2). These four cell lines were not susceptible to the antivirus effect of IFN. In contrast, the multiplication of vesicular stomatitis virus (VSV) was restricted in the nonproducer cell line of IFN, OKM-2 cells by treatment of IFN- α or IFN- γ. Anti-proliferation effect of IFN w as investigated in producer cell line of IFN (MT-2 and SMT-1) and non-producer cell line of IFN (OKM-2). The growth of MT-2 cells was not affected by IFN- α or by IFN- γ. However, SMT-1 and OKM-2 cells were affected by treatment with externally added IFN-α