IMMUNOCYTOCHEMICAL INVESTIGATION OF THE SUBCELLULAR-DISTRIBUTION OF SOME SECRETORY PRODUCTS IN HUMAN SALIVARY-GLANDS

The subcellular distribution of epidermal growth factor (EGF) and of L ewis 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 antig ens, cell surfaces of acini and striated ducts reacted only for difuco sylated antigens; a great number of cytoplasmic vesicles in acinar and ductal cells were reactive for all Lewis antigens and EGF. These resu lts suggest that substances which enter saliva are released not only t hrough granule exocytosis by acinar cells, but also via other routes: the vesicular system revealed in both acinar and ductal cells could pl ay a fundamental role in driving some products both towards the lumen and towards basolateral cell surfaces and intercellular spaces.