Abstract
Production of the fourth component of complement (C4) by the human monocytic cell line U937 and its regulation were investigated in comparison with the production of the third component of complement (C3) in a cell culture system. Although no detectable C4 was produced by U937 without stimulation, U937 was induced by recombinant interferon-gamma (IFN-gamma) to synthesize C4 in a dose- and time-dependent fashion. The production of C4 was reversibly inhibited by cycloheximide, indicating that it resulted from de novo synthesis. The C4 synthesized by U937 cells was functionally active as assessed by haemolytic assay. SDS-PAGE following biosynthetic labelling showed that subunit structure of C4 synthesized by U937 cells was identical with that of plasma C4 but that molecular weight of alpha-chain was greater than that of plasma C4. We compared the regulation of C4 synthesis with that of C3 synthesis. Although C3 synthesis by U937 cells was enhanced by IFN-gamma, lipopolysaccharide (LPS) and phorbol myristate acetate (PMA), C4 synthesis was induced only by IFN-gamma. LPS and IFN-gamma induced a synergistic increase in C3 synthesis by U937 cells. U937 cells incubated with LPS and IFN-gamma synthesized a greater amount of C4 than those incubated with IFN-gamma alone. Thus it was demonstrated that the synthesis of C3 and C4 was independently regulated. This study shows that the U937 cell line provides a useful model for studies on the synthesis of complement proteins and on the regulation of complement production.
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- Barnum S. R., Volanakis J. E. In vitro biosynthesis of complement protein D by U937 cells. J Immunol. 1985 Mar;134(3):1799–1803. [PubMed] [Google Scholar]
- Bengio S., Gilbert D., Peulve P., Daveau M., Fontaine M. Biosynthesis of the third component of complement (C3) by the human monocytic-cell line U-937. Induction by phorbol myristate acetate. Biochem J. 1986 Nov 1;239(3):711–716. doi: 10.1042/bj2390711. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gaither T. A., Alling D. W., Frank M. M. A new one-step method for the functional assay of the fourth component (C4) of human and guinea pig complement. J Immunol. 1974 Aug;113(2):574–583. [PubMed] [Google Scholar]
- Geissler K., Harrington M., Srivastava C., Leemhuis T., Tricot G., Broxmeyer H. E. Effects of recombinant human colony stimulating factors (CSF) (granulocyte-macrophage CSF, granulocyte CSF, and CSF-1) on human monocyte/macrophage differentiation. J Immunol. 1989 Jul 1;143(1):140–146. [PubMed] [Google Scholar]
- Hamilton A. O., Jones L., Morrison L., Whaley K. Modulation of monocyte complement synthesis by interferons. Biochem J. 1987 Mar 15;242(3):809–815. doi: 10.1042/bj2420809. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hortin G., Chan A. C., Fok K. F., Strauss A. W., Atkinson J. P. Sequence analysis of the COOH terminus of the alpha-chain of the fourth component of human complement. Identification of the site of its extracellular cleavage. J Biol Chem. 1986 Jul 5;261(19):9065–9069. [PubMed] [Google Scholar]
- Kulics J., Colten H. R., Perlmutter D. H. Counterregulatory effects of interferon-gamma and endotoxin on expression of the human C4 genes. J Clin Invest. 1990 Mar;85(3):943–949. doi: 10.1172/JCI114523. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- Lappin D. F., Birnie G. D., Whaley K. Modulation by interferons of the expression of monocyte complement genes. Biochem J. 1990 Jun 1;268(2):387–392. doi: 10.1042/bj2680387. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lappin D. F., Whaley K. Interferon-induced transcriptional and post-transcriptional modulation of factor H and C4 binding-protein synthesis in human monocytes. Biochem J. 1990 Nov 1;271(3):767–772. doi: 10.1042/bj2710767. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lappin D., Whaley K. Modulation of monocyte complement synthesis by lymphocytes and lymphocyte-conditioned media. Clin Exp Immunol. 1989 Apr;76(1):86–91. [PMC free article] [PubMed] [Google Scholar]
- Littman B. H., Hall R. E., Muchmore A. V. Lymphokine and phorbol (PMA) regulation of complement (C2) synthesis using U937. Cell Immunol. 1983 Feb 15;76(1):189–195. doi: 10.1016/0008-8749(83)90360-x. [DOI] [PubMed] [Google Scholar]
- Malhotra V., Sim R. B. Expression of complement factor H on the cell surface of the human monocytic cell line U937. Eur J Immunol. 1985 Sep;15(9):935–941. doi: 10.1002/eji.1830150913. [DOI] [PubMed] [Google Scholar]
- Minta J. O. Synthesis of complement factor B by the human monocyte U-937 cell line. Augmentation by immunostimulatory agents. J Immunol. 1988 Sep 1;141(5):1636–1641. [PubMed] [Google Scholar]
- Perlmutter D. H., Colten H. R. Molecular immunobiology of complement biosynthesis: a model of single-cell control of effector-inhibitor balance. Annu Rev Immunol. 1986;4:231–251. doi: 10.1146/annurev.iy.04.040186.001311. [DOI] [PubMed] [Google Scholar]
- Randazzo B. P., Dattwyler R. J., Kaplan A. P., Ghebrehiwet B. Synthesis of C1 inhibitor (C1-INA) by a human monocyte-like cell line, U937. J Immunol. 1985 Aug;135(2):1313–1319. [PubMed] [Google Scholar]
- Schreiber R. D., Müller-Eberhard H. J. Fourth component of human complement: description of a three polypeptide chain structure. J Exp Med. 1974 Nov 1;140(5):1324–1335. doi: 10.1084/jem.140.5.1324. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sundström C., Nilsson K. Establishment and characterization of a human histiocytic lymphoma cell line (U-937). Int J Cancer. 1976 May 15;17(5):565–577. doi: 10.1002/ijc.2910170504. [DOI] [PubMed] [Google Scholar]
- Suzuki T., Cooper M. D. Comparison of the expression of IL 2 receptors by human T and B cells: induction by the polyclonal mitogens, phorbol myristate acetate, and anti-mu antibody. J Immunol. 1985 May;134(5):3111–3119. [PubMed] [Google Scholar]
- Tsukamoto H., Ueda A., Nagasawa K., Tada Y., Niho Y. Increased production of the third component of complement (C3) by monocytes from patients with systemic lupus erythematosus. Clin Exp Immunol. 1990 Nov;82(2):257–261. doi: 10.1111/j.1365-2249.1990.tb05436.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Whaley K. Biosynthesis of the complement components and the regulatory proteins of the alternative complement pathway by human peripheral blood monocytes. J Exp Med. 1980 Mar 1;151(3):501–516. doi: 10.1084/jem.151.3.501. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zuckerman S. H., Schreiber R. D. Up-regulation of gamma interferon receptors on the human monocytic cell line U937 by 1,25-dihydroxyvitamin D3 and granulocyte-macrophage colony stimulating factor. J Leukoc Biol. 1988 Sep;44(3):187–191. doi: 10.1002/jlb.44.3.187. [DOI] [PubMed] [Google Scholar]