Localization of intermediate filament proteins in various structures of the human placenta as revealed by immunoperoxidase technique.

Formalin-fixed, paraffin embedded fragments of normal human placenta were subjected to immunoperoxidase technique with the use of Dako Kits appropriate for detection of vimentin, desmin, and cytokeratins (K 660, 530, and 518 respectively). Distribution of the intermediate filament proteins in syncytiotrophoblast, connective tissue of villous stroma, walls of blood vessels as well as in cells of basal plate and placental islets was compared. General pattern of staining and its localization was characteristic for each of the 3 types of antibodies. In spite of that, most structures observed revealed the presence of more than one type of intermediate filament proteins, with the exception of syncytiotrophoblast containing cytokeratins only. Staining of blood serum and of connective tissue matrix with anti-desmin and anti-cytokeratin antibodies was also observed, whereas fibrinoid remained always negative.