Ultrastructural localization of blood group antigens in human exocrine pancreas by immunogold labelling

The cytochemical distribution of ABH and Lewis antigens was investigated in human pancreas by means of a post-embedding immunogold staining method which permitted antigens associated with secretory materials to be distinguished from those bound to cell surfaces. H and Le-b antigens were found in secretory granules of acinar and interlobular duct cells. In the form of surface-associated antigens, H and Le-b were found in acini and interlobular ducts, Le-a in intralobular ducts. In ductal cells, the same antigens detected in cell surfaces were also found in small cytoplasmic vesicles. It is suggested that by the emptying of these vesicles blood group antigens may be released both into the lumen and into the interstitial spaces.