title: Complement biosynthesis in vitro by rat hepatoma cell strains.
abstract: Four separate rat hepatoma strains were examined for their capacity to synthesize complement (C). None of the strains synthesized detectable amounts of the first components (C-1), and only one strain (7800C-1) produced the fourth component (C4). However, each of the strains synthesized significant amounts of biologically active C-2 and C-3. Three of the four strains also produced C-5 and the natural inhibitor of C-1 (C1 INH). Two control rat cell strains (fibroblast and pituitary) did not synthesize any detectable C components. Production of C, studied extensively in 7800C-1 and H-4, was reversibly inhibited by cycloheximide (2 mug/ml) and [ 14-C ] amino acids were incorporated into C-2, C-3, and C-1 INH. As assessed by gel filtration, the elution positions of the C components synthesized by the cells in culture were similar to those of the corresponding proteins in normal rat serum. Hydrocortisone (10-6 to 10-7 M) stimulated the production of C-3 by H-4 but C-2 and C-5 production were not affected. These C-producing hepatoma cells may prove useful for studies of the control of C biosynthesis.
mesh_terms: D000818:Animals; D001345:Autoradiography; D002250:Carbon Radioisotopes; D006528:Carcinoma, Hepatocellular / Q000276:immunology*; D002460:Cell Line; D002478:Cells, Cultured; D002850:Chromatography, Gel; D003169:Complement Inactivator Proteins; D003165:Complement System Proteins / Q000096:biosynthesis*; D003513:Cycloheximide / Q000494:pharmacology; D004912:Erythrocytes / Q000276:immunology; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D007106:Immune Sera; D005779:Immunodiffusion; D007122:Immunoelectrophoresis; D007532:Isoleucine / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D008113:Liver Neoplasms; D008239:Lysine / Q000378:metabolism; D008297:Male; D011817:Rabbits / Q000276:immunology; D051381:Rats; D012756:Sheep / Q000276:immunology; D014633:Valine / Q000378:metabolism
chemical_list: D002250:Carbon Radioisotopes; D003169:Complement Inactivator Proteins; D007106:Immune Sera; D007532:Isoleucine; D003165:Complement System Proteins; D003513:Cycloheximide; D007930:Leucine; D014633:Valine; D008239:Lysine; D006854:Hydrocortisone