title: Differential effects of type I IFN and IFN-gamma on the binding of tumor necrosis factor to receptors in two human cell lines.
abstract: The effect of IFN-alpha and IFN-beta on the expression of cell surface receptors for tumor necrosis factor (TNF) was examined in two human cell lines. In HeLa cells, IFN-alpha and IFN-beta increased 125I-TNF binding, whereas in HT-29 cells these two IFN either slightly decreased or had no effect on 125I-TNF binding. In contrast, IFN-gamma increased 125I-TNF binding in both cell lines. Both IFN-alpha and IFN-beta exerted an antagonistic effect on IFN-gamma-induced stimulation of TNF receptor expression in HT-29 cells, but did not inhibit TNF receptor induction by IFN-gamma in HeLa cells. IFN-gamma and, to a lesser extent, IFN-beta were synergistic with TNF in producing cytotoxic/cytostatic activity in HT-29 cells. Despite the inhibitory effect of IFN-beta on the IFN-gamma-induced stimulation of TNF receptor expression, IFN-beta did not inhibit the synergistic enhancement of TNF cytotoxicity by IFN-gamma in HT-29 cells. The dissociation between the effects of IFN-beta on TNF receptor expression and on the cytotoxic activity of TNF in HT-29 cells suggests that TNF receptor modulation is not a major mechanism of synergism between IFN and TNF.
mesh_terms: D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D007370:Interferon Type I / Q000494:pharmacology*; D007371:Interferon-gamma / Q000494:pharmacology*; D008970:Molecular Weight; D011485:Protein Binding / Q000187:drug effects; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha
chemical_list: D006023:Glycoproteins; D007370:Interferon Type I; D011956:Receptors, Cell Surface; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma