Ultrastructural localization of alpha-L-fucose, factor VIII related antigen and vimentin in endothelial cells of human skin blood vessels using the low temperature embedding technique with Lowicryl K4M

Abstract

The present study was performed to investigate the ultrastructural localization of the binding sites of the lectin Ulex europaeus agglutinin, Type I (UEA) and the antibody against factor VIII related antigen (F VIII RAG), both widely used as vascular markers in human skin capillaries at light microscopy level. In addition the ultrastructural localization of vimentin, the major protein of the endothelial intermediate filaments, was demonstrated in human vascular endothelial cells (EC) in situ. The low temperature postembedding technique with Lowicryl K4M with subsequent application of gold labelled antibodies provided both well preserved antigenicity and morphology. The antigenic site of UEA, alpha-L-fucose containing glycohydrate residues, was primarily found in or near the luminal plasma membrane of EC. Gold particles representing the sites of F VII RAG were located in the Weibel-Palade bodies (WPB) of EC. The ultrastructural staining pattern of the anti-vimentin antibody showed an exclusive labelling of the intermediate filaments of EC.