title: Interferon-alpha/beta, pentoxifylline, and caffeine synergize with interferon-gamma to induce major histocompatibility complex class I expression on a constitutively class I-negative murine tumor cell line.
abstract: The constitutively class I-negative tumor cell line, Kgv, expresses H-2Dk in response to interferon-gamma (IFN-gamma), but not in response to IFN-alpha/beta, tumor necrosis factor, or lymphotoxin. H-2Dk expression was not induced on Kgv cells by the methylxanthines, pentoxifylline (PTX) and caffeine, which modulate class I expression on cells that constitutively express class I molecules. Treatment of Kgv cells with either IFN-alpha/beta, PTX, caffeine, or dibutyryl cAMP and a concentration of IFN-gamma insufficient by itself to induce Dk expression resulted in the induction of Dk expression. Since PTX and caffeine are cAMP-specific phosphodiesterase inhibitors, it is possible that the effects of PTX, caffeine, and dibutyryl cAMP involve a cAMP-dependent mechanism. We conclude that concentrations of IFN-gamma insufficient to induce Dk expression on Kgv cells may be capable of rendering the Dk gene responsive to signals that, in the absence of IFN-gamma treatment, have no effect on Dk expression.
authors.affiliation: University of Pennsylvania, Philadelphia 19104.
authors.forename: L A
authors.initials: LA
authors.lastname: Rosenthal
authors.forename: K K
authors.initials: KK
authors.lastname: Klyczek
authors.forename: K J
authors.initials: KJ
authors.lastname: Blank
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D002110:Caffeine / Q000494:pharmacology*; D016207:Cytokines / Q000494:pharmacology; D003995:Dibutyryl Cyclic GMP / Q000494:pharmacology; D004357:Drug Synergism; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D005805:Genes, MHC Class I / Q000187:drug effects*; D006681:HLA-D Antigens / Q000378:metabolism*; D007370:Interferon Type I / Q000494:pharmacology*; D007371:Interferon-gamma / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010431:Pentoxifylline / Q000494:pharmacology*; D011994:Recombinant Proteins; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D016207:Cytokines; D006681:HLA-D Antigens; D007370:Interferon Type I; D011994:Recombinant Proteins; D003995:Dibutyryl Cyclic GMP; D002110:Caffeine; D007371:Interferon-gamma; D010431:Pentoxifylline