An immunohistochemical study of normal human neonate and adult parotid gland tissue. Detection of lysozyme, lactoferrin, a1-antichymotrypsin, a1-antitrypsin and carcinoembryonic antigen.

The immunohistochemical detection and distribution of lysozyme (Ly), Lactoferrin (Lf), a1-Antichymotrypsin (a1-AChy), a1-Antitrypsin (a1-AT) and Carcinoembryonic antigen (CEA) were studied in neonate and adult parotid gland tissue, using the peroxidase-antiperoxidase (PAP) method. Ly stain in neonates extended into acini, intercalated ducts and occasional cells of large ducts, whereas in adults Ly was usually confined to the intercalated ducts. The distribution pattern of Lf in neonates varied considerably between individual glands showing three staining patterns. Most of the intercalated ducts, some groups of acini and rare striated duct cells were positive for Lf in adults. a1-AChy and a1-AT in neonates were positive mainly in the large ducts, whereas staining for a1-AChy and a1-AT in adults frequently extended into some intercalated duct cells, although less intensively. Finally, CEA in neonates was localized in the lumina and luminal membranes of the acini, in intercalated ducts, and less frequently in the large ducts. In adults CEA was present predominantly in the lumina and luminal membranes of the intercalated duct cells. These differences may suggest an immunohistochemical postnatal differentiation of the parotid gland.