The Journal of Immunology, Vol 147, Issue 12 4218-4223, Copyright © 1991 by American Association of Immunologists

ARTICLES

Production of IL-1 receptor antagonist by human in vitro-derived macrophages. Effects of lipopolysaccharide and granulocyte-macrophage colony-stimulating factor

RW Janson, KR Hance and WP Arend
Rheumatology Section, Medical Service, Denver Veterans Administration Medical Center, CO 80220.

The objective of these experiments was to evaluate the production of IL- 1ra, a specific receptor antagonist of IL-1, by human in vitro-derived macrophages, a model for differentiated macrophages. IL-1ra protein levels in supernatants and lysates of cultured cells were determined by a specific ELISA. Relative steady-state IL-1ra mRNA levels were measured using a specific cDNA probe. Human monocytes were differentiated by 6 days culture in either medium or granulocyte- macrophage colony-stimulating factor (GM-CSF), after which the effects of subsequent LPS and/or GM-CSF on the production of IL-1ra were evaluated. In vitro-derived macrophages cultured in medium for 6 days constitutively produced IL-1ra protein during the 24-h period of the 7th day in culture. The constitutive production of IL-1ra by medium- aged cells correlated with low steady-state IL-1ra mRNA levels determined over this same time period. In contrast, cells cultured for 6 days in GM-CSF synthesized significantly increased levels of IL-1ra protein during the 7th day in culture but the secreted levels remained unchanged. Cells differentiated in GM-CSF displayed enhanced steady- state levels of IL-1ra mRNA in comparison with cells aged in medium. Stimulation of in vitro-derived macrophages aged for 6 days in medium or in GM-CSF, with LPS or adherent IgG, did not result in increased levels of IL-1ra protein production in comparison with non-LPS stimulated cells. The IL-1ra protein detected in the supernatants of cells differentiated in GM-CSF was biologically active in the IL-1- augmented murine thymocyte proliferation assay. By Western blot analysis, the IL-1ra protein in the in vitro-derived macrophage supernatants was predominantly the 22- to 24-kDa glycosylated species, whereas the lysates contained additional lower molecular weight forms. These results suggest that as monocytes differentiate in vitro into macrophages, they constitutively produce IL-1ra protein and that this production is enhanced by the continuous presence of GM-CSF.

This article has been cited by other articles:

				M. Ditiatkovski, B.-H. Toh, and A. Bobik GM-CSF Deficiency Reduces Macrophage PPAR-{gamma} Expression and Aggravates Atherosclerosis in ApoE-Deficient Mice Arterioscler. Thromb. Vasc. Biol., October 1, 2006; 26(10): 2337 - 2344. [Abstract] [Full Text] [PDF]

				C. Dumas, A. Muyombwe, G. Roy, C. Matte, M. Ouellette, M. Olivier, and B. Papadopoulou Recombinant Leishmania major Secreting Biologically Active Granulocyte-Macrophage Colony-Stimulating Factor Survives Poorly in Macrophages In Vitro and Delays Disease Development in Mice Infect. Immun., November 1, 2003; 71(11): 6499 - 6509. [Abstract] [Full Text] [PDF]

				A. L. Lambert, F. S. Trasti, J. B. Mangum, and J. I. Everitt Effect of Preexposure to Ultrafine Carbon Black on Respiratory Syncytial Virus Infection in Mice Toxicol. Sci., April 1, 2003; 72(2): 331 - 338. [Abstract] [Full Text] [PDF]

				J. H. Von der Thusen, J. Kuiper, T. J. C. Van Berkel, and E. A. L. Biessen Interleukins in Atherosclerosis: Molecular Pathways and Therapeutic Potential Pharmacol. Rev., March 1, 2003; 55(1): 133 - 166. [Abstract] [Full Text] [PDF]

				M CUTOLO, A SULLI, C PIZZORNI, B SERIOLO, and R H STRAUB Anti-inflammatory mechanisms of methotrexate in rheumatoid arthritis Ann Rheum Dis, August 1, 2001; 60(8): 729 - 735. [Full Text] [PDF]

				J. S. H. Liu, T. D. Amaral, C. F. Brosnan, and S. C. Lee IFNs Are Critical Regulators of IL-1 Receptor Antagonist and IL-1 Expression in Human Microglia J. Immunol., August 15, 1998; 161(4): 1989 - 1996. [Abstract] [Full Text] [PDF]

				J. Sivo, C.A. Salkowski, A.D. Politis, and S.N. Vogel Differential regulation of LPS-induced IL-1 and EL-1 receptor antagonist mRNA by IFN{alpha} and IFN{gamma} in murine peritoneal macrophages Innate Immunity, March 1, 1994; 1(1): 30 - 37. [Abstract] [PDF]