title: The third component of complement is transcribed and secreted by cultured human endothelial cells.
abstract: Monotypic cultures of passaged human umbilical vein endothelial cells secrete C3 protein, which is specifically immunoprecipitable from cell lysates and conditioned medium. A transcript migrating at 5.3 kilobases hybridizes with a mouse-derived C3 DNA probe in parallel cultures of endothelial cells, hepatoma cells (HepG2), and freshly isolated human monocytes. Steady-state transcript levels were as follows: HepG2 cells, 1.0; monocytes, 0.05; endothelial cells, 0.01. These data suggest that C3, an indispensible component for activation of complement by both the classical and alternative pathways, is locally synthesized in the vascular bed.
mesh_terms: D002478:Cells, Cultured; D003176:Complement C3 / Q000235:genetics / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000276:immunology*; D006801:Humans; D009693:Nucleic Acid Hybridization; D011233:Precipitin Tests; D012313:RNA / Q000302:isolation & purification; D014158:Transcription, Genetic
chemical_list: D003176:Complement C3; D012313:RNA