Actin containing cells in normal human salivary glands

Summary A study of actin distribution in human salivary glands was performed, using smooth muscle antibodies from a patient with active chronic hepatitis.Immunoperoxidase labelling methods were found to give a good staining intensity for actin containing cells. The peroxidase antiperoxidase (PAP) method gave a stronger reaction than the double layer method, but the latter was sensitive enough for our purpose and was less time consuming. Sections from formalin fixed and paraffin embedded specimens were negative for actin staining while frozen sections showed good staining results. Sections from specimens which were washed for 12 h at 4 ° C showed less background staining.Strong staining was found in myoepithelial cells lying around the acini, intercalated ducts and parts of the striated ducts. The number of myoepithelial cells around acini increased in the following order: the parotid gland, the submandibular gland, the sublingual gland and the small glands of the lip. This distribution indicates the importance of myoepithelial cells in the process of physical expression of saliva. Cytoplasmic staining in the basal epithelial cells of the striated ducts illustrates that these cells may be involved in some sort of secretion. This staining might also suggest a histogenetic origin for myoepithelial cells.