title: Induction of membrane-associated interleukin 1 by tumor necrosis factor in human fibroblasts.
abstract: Highly purified recombinant human tumor necrosis factor (TNF) was found to induce interleukin 1 (IL 1) production in diploid human FS-4 fibroblasts. Demonstration of IL 1 activity was based on the ability of TNF-treated FS-4 cells, subsequently fixed with formaldehyde, to stimulate thymocyte proliferation in the presence of phytohemagglutinin. Incubation of FS-4 cells with the optimal dose of TNF (10 ng/ml) resulted in a marked increase in [3H] thymidine uptake by thymocytes co-cultured with formaldehyde-fixed FS-4 cells. Induction of this apparently membrane-associated IL 1 (MA-IL 1) activity was demonstrable at 6 hr and reached a plateau after 48 hr of incubation with TNF. FS-4 cells did not secrete soluble IL 1 in response to TNF. Dexamethasone suppressed the synthesis of TNF-induced MA-IL 1. A monoclonal antibody specific for TNF neutralized MA-IL 1 induction, indicating that the induction is due to TNF, and not to a contaminant in the TNF preparation. The ability of TNF to induce IL 1 synthesis in FS-4 fibroblasts at the transcriptional level was confirmed by S1 nuclease protection assay. Cytoplasmic RNA from uninduced FS-4 cells contained no demonstrable RNA hybridizing with a human IL 1-alpha cDNA probe and low levels of RNA hybridizing with an IL 1-beta cDNA. Induction with TNF resulted in the appearance of IL 1-alpha mRNA and a very significant increase in IL 1-beta mRNA, indicating that TNF induces the synthesis of both IL 1-alpha and IL 1-beta in FS-4 cells.
mesh_terms: D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000378:metabolism*; D006023:Glycoproteins / Q000494:pharmacology*; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis* / Q000235:genetics; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics; D013601:T-Lymphocytes / Q000166:cytology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha
chemical_list: D006023:Glycoproteins; D007375:Interleukin-1; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D003907:Dexamethasone