Immunocytochemical localization of factor VIII/von Willebrand factor antigen in human platelets.
Specific antibodies against anti-human FVIII/vW protein were isolated by affinity chromatography on glutaraldehyde-activated gel (Ultrogel AcA22). They were coupled directly with peroxidase or visualized with anti-rabbit IgG (sheep)-peroxidase (Institut Pasteur). Fab fragments of the same specific antibodies were prepared to enhance the intracellular penetration and coupled to peroxidase. In washed human platelets, staining was observed on the plasma membrane and in the canalicular system, whereas in previous studies whole specific antibodies incubated with fixed platelets showed the labeling only on the plasma membrane. After thrombin activation, the release of granules containing FVIII/vW protein was better visualized in the surface canalicular system. This localization was discussed in regard to the exocytosis process: membrane fusion, granule labeling.
D000941:Antigens / Q000032:analysis*; D001792:Blood Platelets / Q000276:immunology*; D002462:Cell Membrane / Q000276:immunology; D006651:Histocytochemistry; D006801:Humans; D007124:Immunoenzyme Techniques; D007140:Immunoglobulin Fab Fragments; D008561:Membrane Fusion; D008854:Microscopy, Electron; D014841:von Willebrand Factor / Q000276:immunology
D000941:Antigens; D007140:Immunoglobulin Fab Fragments; C029417:Von Willebrand antigen; D014841:von Willebrand Factor