Human Labial Gland Duct Epithelium and slgA Secretion An Ultrastructural and Immunohistochemical Study
Objectives/Hypothesis : The aim of the present study was to clarify the variety of cell components, including acinous secretory cells and duct epithelial cells, of the labial glands, which participate in secretory IgA (slgA) secretion. Study Design : An ultrastructural and immunohistochemical investigation. Methods : Using five autopsied cases, both secretory and duct portions of the human labial glands were examined ultrastructurally, and immunohistochemical observations of IgA, IgG, IgM, secretory component (SC) and lysozyme were performed using the avidin-biotin peroxidase complex (ABC) method. Results : The secretory portions consisted of two types of secretory cells, seromucous cells and serous cells. The gland had long intralobular ducts with short intercalated ducts. The intralobular duct epithelium consisted of four types of epithelial cells ; D-l, D-2, D-3 and D-4 cells. Immunohistochemically, epithelial cells (especially D-l cells) and intercalated duct cells were, strongly stained not only by immunoglobulins but also by SC. D-3 cells were lysozyme positive. Conclusion: In human labial glands, secretory cells and both D-l epithelial cells of the intralobular duct and intercalated duct cells were considered to be responsible for slgA secretion and lysozyme secretion.