SIMPLE MUCIN-TYPE CARBOHYDRATE ANTIGENS IN MAJOR SALIVARY-GLANDS

Simple mucin-type carbohydrate antigens Tn, sialosyl-Tn and T are ofte n markers of neoplastic transformation and have very limited expressio n in normal tissues. We performed an immunohistological study of simpl e mucin-type carbohydrate antigens, including H and A variants, with w ell-defined monoclonal antibodies (MAb) on frozen and paraffin-embedde d normal salivary gland tissue from 22 parotid, 14 submandibular, six sublingual, and 13 labial glands to elucidate the simple mucin-type gl ycosylation pattern in relation to cyto- and histodifferentiation. The investigated carbohydrate structures were predominantly observed in t he cell cytoplasm, most often in the supranuclear area, suggesting loc alization to the Golgi region, whereas ductal contents were unstained. Mucous acinar cells expressed Tn, sialosyl-Tn, and H and A antigens, regardless of glandular location. Serous acinar cells, on the other ha nd, expressed A, H, and inconstantly sialosyl-T, Tn, and sialosyl-Tn a ntigens in major salivary glands, whereas serous cells of minor (labia l) salivary glands expressed H exclusively, Tn and sialosyl-T antigens inconstantly, but never sialosyl-Tn and A antigens. The difference ma y be related to a more simple cytodifferentiation of serous cells of m inor (labial) salivary glands as compared with major salivary glands. Duct cells in major salivary glands expressed A, H, and inconstantly T , sialosyl-T, and Tn antigen, whereas minor (labial) salivary glands d ucts exclusively expressed H, T and sialosyl-T antigens, differences t hat may be related to dissimilarities in the duct system. Myoepithelia l cells and basal cells exclusively expressed T and sialosyl-T antigen s, which may prove useful in studies of salivary gland tumors, since t hese cells are known to play a key role in the histological characteri stics of some salivary gland tumors. The results indicate a similar gl ycosylation pattern in the different major salivary glands, whereas mi nor (labial) salivary gland differ slightly in serous and duct cells. The limited and exclusive intracellular expression of the immature Tn, sialosyl-Tn, and T antigens indicates that these structures may be of value as markers of salivary gland tumors.