Immunocytochemical investigation of the subcellular distribution of some secretory products in human salivary glands.

The subcellular distribution of epidermal growth factor (EGF) and of Lewis antigens was demonstrated by means of a post-embedding immunogold cytochemical method in human parotid and submandibular gland. Acinar secretory granules were reactive for EGF and difucosylated Lewis antigens, cell surfaces of acini and striated ducts reacted only for difucosylated antigens; a great number of cytoplasmic vesicles in acinar and ductal cells were reactive for all Lewis antigens and EGF. These results suggest that substances which enter saliva are released not only through granule exocytosis by acinar cells, but also via other routes: the vesicular system revealed in both acinar and ductal cells could play a fundamental role in driving some products both towards the lumen and towards basolateral cell surfaces and intercellular spaces.