title: Constitutive production and characterization of interferon-gamma in a human T-lymphoblastoid cell line transformed by a human retrovirus.
abstract: A human T-lymphoblastoid cell line, TCL-Fuj, constitutively produced a large amount of human gamma interferon (IFN) in culture fluids and has sustained stable IFN production for more than two years. When cells were incubated in RPMI-1640 medium with 10% fetal calf serum for three days, IFN activity was detectable at a cell density of 6 X 10(4) cells/ml, whereas 2,000-16,000 units of IFN per ml were produced at 5-10 X 10(5) cells/ml. IFN production was also detected even in serumfree medium and as early as 2 hr after cultivation in fresh medium. IFN was inhibited by treatment of cells with either actinomycin D or cycloheximide, indicating the requirement of IFN-mRNA and protein for de novo synthesis. The molecular weight of the IFN was 45,000-60,000 as determined by Sephacryl S200 gel filtration. Two activity peaks corresponding to molecular weights of 22,000 and 39,000 were obtained by SDS-polyacrylamide gel electrophoresis. Analysis by isoelectric focusing revealed charge heterogeneity with four species at pIs of 6.0, 7.1, 8.6, and 9.3. Conventional IFN-gamma inducers, concanavalin A and 12-O-tetradecanoyl-phorbol-13-acetate, further enhanced the production of IFN in this cell line.
mesh_terms: D002460:Cell Line; D002472:Cell Transformation, Viral; D003208:Concanavalin A / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D017977:Deltaretrovirus / Q000502:physiology; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000302:isolation & purification; D007700:Kinetics; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D003208:Concanavalin A; D003609:Dactinomycin; D007371:Interferon-gamma; D013755:Tetradecanoylphorbol Acetate