title: Terminal complement complex and endothelial cells.
abstract: The effects of the terminal complement sequence on two endothelial cell functions (prostacyclin (PGI2) generation and permeability of an endothelial cell monolayer) were examined in antibody-sensitized pulmonary artery endothelial cells. Whereas C5b-7 complement complexes induced on PGI2 formation and no enhanced endothelial permeability, addition of purified complement component C8 resulted in a time- and dose-dependent burst of PGI2 release and in a substantially increased permeability of an endothelial cell monolayer in the absence of overt cell damage. Formation of the complete terminal complement complex C5b-9 enhanced PGI2 release but was accompanied by cytolysis. Extracellular Ca2+ was required for C5b-8 dependent PGI2 formation. Three different blockers of physiological calcium channels failed to suppress the observed stimulatory effect. One minute after addition of C8 to endothelial cells carrying C5b-7 complexes, a six to sevenfold enhanced passive influx of 45Ca2+ into the cells was noted. An enhanced passive influx was also observed for 51CrO4(2-), 3H-aminobutyric acid, and 3H-sucrose, but not for 3H-inulin and 3H-dextran. These data together suggest that complement C5b-8 complexes may serve as Ca2+-bypass gates in endothelial cells, the ensuing influx of Ca2+ leading to subsequent activation of the arachidonic acid pathway and the actin-myosin system.
authors.affiliation: Department of Internal Medicine, University of Giessen, FRG.
authors.forename: N
authors.initials: N
authors.lastname: Suttorp
authors.forename: S
authors.initials: S
authors.lastname: Bhakdi
mesh_terms: D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000502:physiology*; D002478:Cells, Cultured; D003167:Complement Activation / Q000502:physiology; D003182:Complement C5 / Q000502:physiology*; D050776:Complement C5b; D004730:Endothelium, Vascular / Q000276:immunology*; D011464:Epoprostenol / Q000378:metabolism; D006801:Humans
chemical_list: D001095:Arachidonic Acids; D003182:Complement C5; D016718:Arachidonic Acid; D050776:Complement C5b; D011464:Epoprostenol