title: In vivo and in vitro expression of macrophage membrane interleukin 1 in response to soluble and particulate stimuli.
abstract: We examined the expression of a membrane form of interleukin 1 (IL 1) by macrophages. Murine peritoneal macrophages fixed immediately after harvesting, in suspension, did not show membrane IL 1. Membrane IL 1 was expressed after a 3-hr culture on plastic dishes. These findings allowed us to examine some conditions in vivo that may trigger the expression of this protein; that is, by fixing the macrophages in suspension we could determine if a given stimulus had an effect. We found that membrane IL 1 was expressed briefly after administration of live or dead Listeria monocytogenes or endotoxin. Serum proteins were ineffective. At the time of maximal activation of macrophages by live Listeria, membrane IL 1 was not expressed. Analysis of in vitro conditions indicated that expression of membrane IL 1 and Ia molecules could be dissociated. In culture, recombinant interferon-gamma induced Ia but no membrane IL 1. Uptake of dead Listeria organisms had no effect on Ia but triggered membrane IL 1. The stimulation of membrane IL 1 was not caused by phagocytosis per se: latex particles were ineffective. Opsonized red cells stimulated membrane IL 1 on macrophages that were activated in vivo by inflammatory stimuli.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis; D007274:Injections, Intraperitoneal; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000096:biosynthesis*; D008089:Listeria monocytogenes / Q000276:immunology; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis*; D051379:Mice; D008805:Mice, Inbred A; D008809:Mice, Inbred C3H; D008808:Mice, Inbred CBA
chemical_list: D000949:Histocompatibility Antigens Class II; D007375:Interleukin-1; D008565:Membrane Proteins; D007371:Interferon-gamma