title: Human umbilical vein endothelial cells synthesize functional C3, C5, C6, C8 and C9 in vitro.
abstract: Human endothelial cells (EC), cultured serum-free, synthesize de novo protein which increasingly bind to agarose beads (an alternative pathway activator), until a plateau phase is reached after 24-48 h. EC synthesize functional C3, C5, C6, C8 and C9, which were detected on co-cultured agarose beads, using relevant polyclonal anti-complement antibodies. Two monoclonal anti-C9 neoepitope antibodies (aE11, poly C9-MA) bound to the co-cultured beads, showing that the terminal complement complex (TCC) (C5b-9) was assembled on the beads. This also suggests that C7 is synthesized. There seems to be a positive correlation between the amount of agarose-bound labelled protein and agarose-bound complement. The results indicate that EC produce and secrete the components for the functional alternative and terminal pathways of complement.
authors.affiliation: Department of Surgery, Ullevål Hospital, Oslo, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Johnson
authors.forename: G
authors.initials: G
authors.lastname: Hetland
mesh_terms: D000911:Antibodies, Monoclonal; D002478:Cells, Cultured; D003176:Complement C3 / Q000096:biosynthesis; D003182:Complement C5 / Q000096:biosynthesis; D003183:Complement C6 / Q000096:biosynthesis; D003185:Complement C8 / Q000096:biosynthesis; D003186:Complement C9 / Q000096:biosynthesis; D003165:Complement System Proteins / Q000096:biosynthesis*; D003513:Cycloheximide / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D008863:Microspheres; D011863:Radioimmunoassay; D012685:Sepharose; D014471:Umbilical Veins / Q000166:cytology
chemical_list: D000911:Antibodies, Monoclonal; D003176:Complement C3; D003182:Complement C5; D003183:Complement C6; D003185:Complement C8; D003186:Complement C9; D003165:Complement System Proteins; D012685:Sepharose; D003513:Cycloheximide