Intermediate-sized filaments of human endothelial cells.

Abstract

Human endothelial cells prepared from umbilical cords are characterized in parallel by EM and indirect immunofluorescence microscopy using specific antibodies against different classes of intermediate-sized filaments. The strongly developed, loose bundles of intermediate-sized filaments typically found in these cells are not decorated by antibodies against prekeratin or antibodies against smooth muscle desmin. They are strongly decorated by antibodies directed against murine vimentin, i.e., the 57,000 MW polypeptide which is the major protein of the intermediate-sized filaments predominant in various cells of mesenchymal origin. Cytoskeletal preparations greatly enriched in intermediate-sized filaments show the enrichment of a polypeptide band comigrating with murine vimentin. The intermediate-sized filaments that are abundant in human endothelial cells are predominantly of the vimentin type and can be demonstrated by their cross-reaction with the vimentin of rodents. Several subclasses of intermediate-sized filaments which can be distinguished by immunological procedures probably exist.