Identification of a membrane-associated interleukin 1 in macrophages.
We have found a surface membrane-associated interleukin 1 (IL-1) with potent thymocyte and T-cell stimulatory activity on peptone-elicited peritoneal macrophages. The IL-1 activity was demonstrated on both fixed macrophage monolayers and on isolated membranes from unfixed macrophages. Membrane IL-1 was induced by adherence and/or by adding heat-killed Listeria monocytogenes to macrophage cultures. The macrophage membrane IL-1 was similar functionally and antigenically to soluble IL-1, but its expression could be temporally dissociated from IL-1 secretion; membrane IL-1 was induced earlier and persisted longer than IL-1 secretion during in vitro macrophage culture. Moreover, when cultured macrophages that had ceased both secretion and membrane expression of IL-1 were restimulated by adding heat-killed Listeria, substantial membrane IL-1 was induced in the absence of detectable IL-1 secretion. Membrane IL-1 appears to be an integral membrane protein since it was solubilized by detergent but was not eluted by EDTA, high salt, or low pH treatment of the membranes.
D000818:Animals; D002448:Cell Adhesion; D002462:Cell Membrane / Q000276:immunology; D002478:Cells, Cultured; D007375:Interleukin-1 / Q000096:biosynthesis / Q000302:isolation & purification*; D008089:Listeria monocytogenes / Q000276:immunology; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D013601:T-Lymphocytes / Q000276:immunology
D007375:Interleukin-1