Synthesis of complement factor B by the human monocyte U-937 cell line. Augmentation by immunostimulatory agents
The human pre-monocytic cell line U-937 was shown to synthesize and to secrete increasing amounts of factor B in short term cultures in serum-free medium containing BSA. The kinetics of factor B production were higher on day 2 than on days 1 and 3. The production of factor B was reversibly inhibited by cycloheximide, indicating de novo synthesis. Metabolic labeling with (/sup 35/S)-methionine and SDS-PAGE analysis revealed that both intracellular and secreted factor B were single-chain proteins with similar m.w. (90,000), which co-migrated with purified plasma factor B. Incubation of U-937 cells with the immunostimulants PMA, LPS, IFN-gamma, and IL-1 resulted in a dose-dependent augmentation of factor B production. A 24-h exposure to IL-1 was shown to be required for maximal stimulation. A combination of suboptimal doses of LPS and IFN-gamma was shown to exert a synergistic effect on factor B production. The U-937 cell line is thus a valuable model for the study of the regulation of the factor B gene expression.
- Research Organization:
- Univ. of Toronto, Ontario (Canada)
- OSTI ID:
- 6746306
- Journal Information:
- J. Immunol.; (United States), Vol. 141:5
- Country of Publication:
- United States
- Language:
- English
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
COMPLEMENT
BIOSYNTHESIS
PHORBOL ESTERS
BIOLOGICAL EFFECTS
BIOCHEMICAL REACTION KINETICS
DOSE-RESPONSE RELATIONSHIPS
ELECTROPHORESIS
HEMOLYSIS
INTERFERON
LIPOPOLYSACCHARIDES
LYMPHOKINES
MAN
METHIONINE
MONOCYTES
SULFUR 35
TRACER TECHNIQUES
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CARBOHYDRATES
CARBOXYLIC ACIDS
CARCINOGENS
DAYS LIVING RADIOISOTOPES
DRUGS
ESTERS
EVEN-ODD NUCLEI
GROWTH FACTORS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LEUKOCYTES
LIGHT NUCLEI
LIPIDS
LIPOTROPIC FACTORS
LYSIS
MAMMALS
MATERIALS
MITOGENS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PATHOLOGICAL CHANGES
POLYSACCHARIDES
PRIMATES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
SACCHARIDES
SULFUR ISOTOPES
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques
560300 - Chemicals Metabolism & Toxicology