Cytochemical localization of blood group substances in human salivary glands using lectin-gold complexes

We investigated localization of blood group antigens and their related substances in human labial salivary and submandibular glands by application of a post-embedding cytochemical staining procedure using lectin- or glycoprotein-gold complexes. Surgical tissue was obtained from 10 patients. Blood group-specific lectins, such as Dolichos biflorus agglutinin or Helix pomatia agglutinin (group A-specific), Griffonia simplicifolia agglutinin-I B4 (group B-specific), and Ulex europaeus agglutinin I (group H-specific) could recognize A, B, and H antigens, respectively, only in mature secretory granules (mature SG), which were found preferentially in cells in the late phase of the maturation cycle. In immature secretory granules (immature SG), which were found in cells in the early or middle phase of the maturation cycle, no binding with these lectins was observed. The Golgi complexes and endoplasmic reticula also were not labeled with these lectins. In blood group O and B secretors, blood group antigens were uniformly distributed throughout all the mature SG examined. However, in blood group A secretors, the distribution was heterogeneous, i.e., in some granules only H antigen was demonstrated, whereas in others both A antigens and a small amount of H antigens were detected. Among the blood group-nonspecific lectins, wheat germ agglutinin (WGA) was found to bind more preferentially to immature SG than to mature SG. This was demonstrated irrespective of the blood group and secretor status of the tissue donor, except that in blood group A secretors WGA bound strongly to some mature SG which possessed A antigen. We discuss the significance of cellular and subcellular mosaic distribution of blood group antigens in connection with morphological differences of secretory granules and the maturation cycle of mucous cells.