title: Demonstration of IL-1 alpha, and IL-1 beta secretion by the monocytic leukemia cell line, THP-1.
abstract: This study examined the secretion of IL-1 alpha and IL-1 beta by THP-1 leukemia cells following activation with mezerein and promotion of synthesis by interferon (IFN-gamma). Interleukin-1 (IL-1) was not detected by co-mitogenic thymocyte assays of crude supernates. Isoelectrofocusing of concentrated medium showed that all biologically active IL-1 migrated at a pH of 6.8-7.2, indicating that the major secreted form was IL-1 beta. Double antibody ELISA confirmed the presence of IL-1 beta, but failed to detect IL-1 alpha in isofocused fractions. Although it appeared that THP-1 cells do not secrete IL-1 alpha; an inhibitor of thymocyte response to IL-1 was present in conditioned medium, migrated in an acidic pH range and masked the expression of biologically active rIL-1 alpha and rIL-1 beta. In contrast, IL-1 alpha was detected using a cell blotting assay. This technique permitted visualization of subpicogram levels of IL-1 when secreted by cells attached to an immunoblotting paper. Cell blotting showed that a greater proportion of attached cells incubated for 24 h in medium containing mezerein and IFN-gamma secreted IL-1 than cells in control medium. In conclusion, the amount of immunoreactive or biologically active IL-1 alpha secreted by stimulated THP-1 cells appeared to be much lower than that reported for human peripheral blood monocytes.
authors.affiliation: Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802.
authors.forename: E V
authors.initials: EV
authors.lastname: Gaffney
authors.forename: C R
authors.initials: CR
authors.lastname: Stoner
authors.forename: S E
authors.initials: SE
authors.lastname: Lingenfelter
authors.forename: L A
authors.initials: LA
authors.lastname: Wagner
mesh_terms: D004224:Diterpenes; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000378:metabolism*; D007948:Leukemia, Monocytic, Acute / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D013729:Terpenes / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D004224:Diterpenes; D007375:Interleukin-1; D008070:Lipopolysaccharides; D013729:Terpenes; C011309:mezerein; D007371:Interferon-gamma