Simple Mucin-Type Carbohydrates in Oral Stratified Squamous and Salivary Gland Epithelia

Simple mucin-type carbohydrate antigens, T, Tn, and sialosysl-Tn, have been found to be good markers of malignant transformation in several epithelial tissues as a result of incomplete synthesis with precursor accumulation. The T, Tn, and sialosy-Tn antigens represent the initial, most immature glycosylation of serine and threonine amino acids of proteins. In normal adult cells these structures are generally masked by addition of further saccharides to form more complex structures. We analyzed simple mucin-type carbohydrates in human labial stratified squamous and minor salivary gland epithelia in order to define the glycosylation pattern in normal cells in relation to epithelial differentiation and maturation. A panel of monoclonal antibodies with well-characterized specificity for T, Tn, sialosyl-Tn and the histo-blood group H and A variants hereof were used in immunohistology of section from 30 individuals with known ABO, Lewis, and secretor status. In stratified epithelium the sialylated T structure was confined to cell membranes of immature based cells, whereas the H and A variants were observed on cell layers. Furthermore, superficial spinous cells produced a fine granular cytoplasmic staining for Tn and sialosyl-Tn and sialosyl-Tn as well as the H and A variants in the area of the nucleus, whereas T and the H variant were found in duct cells and unsubstituted T antigen in myoepithelial cells. These results indicate that incomplete synthesis, i.e., deletion of sialytransferases and/or histo-blood group ABH transferases, may result in accumulation of T, Tn, and sialosyl-Tn antigens in oral epithelia, thus offering a baseline for further studies of changes in premalignant and malignant oral epithelia