title: The ultrastructural localization of von Willebrand factor in endothelial cells.
abstract: Factor VIII-related antigen was localized ultrastructurally in a variety of human tissues (smooth muscle, skeletal muscle, breast, capillary hemangioma) with the use of a low-temperature embedding protein A-gold technique with both polyclonal and monoclonal antisera directed against von Willebrand factor. All endothelial cells examined localized the anti-von Willebrand factor to Weibel-Palade bodies. Cisternae of the endoplasmic reticulum, and cytoplasmic vacuoles were also labeled. These results establish the distribution of factor VIII-related antigen at the subcellular level. The observed distribution suggests that the endothelial cells synthesize von Willebrand factor, store it in Weibel-Palade bodies, and release it by exocytosis. These observations provide in vivo confirmation for previous biochemical and immunocytochemical data obtained from studies on cultured endothelial cells.
mesh_terms: D000941:Antigens / Q000032:analysis / Q000276:immunology; D001779:Blood Coagulation Factors / Q000032:analysis*; D004727:Endothelium / Q000378:metabolism / Q000648:ultrastructure*; D005169:Factor VIII / Q000032:analysis / Q000276:immunology; D006391:Hemangioma / Q000648:ultrastructure; D006651:Histocytochemistry; D006801:Humans; D007120:Immunochemistry; D002479:Inclusion Bodies / Q000648:ultrastructure; D009131:Muscle, Smooth, Vascular / Q000648:ultrastructure; D014841:von Willebrand Factor / Q000032:analysis* / Q000096:biosynthesis / Q000276:immunology
chemical_list: D000941:Antigens; D001779:Blood Coagulation Factors; D014841:von Willebrand Factor; D005169:Factor VIII