ULTRASTRUCTURAL-LOCALIZATION OF BLOOD-GROUP ANTIGENS IN HUMAN EXOCRINE PANCREAS BY IMMUNOGOLD LABELING

The cytochemical distribution of ABH and Lewis antigens was investigat ed 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 antige ns were found in secretory granules of acinar and interlobular duct ce lls. In the form of surface-associated antigens, H and Le-b were found in acini and interlobular ducts, Le-a in intralobular ducts. In ducta l cells, the same antigens detected in cell surfaces were also found i n small cgtoplasmic vesicles. It is suggested that by the emptying of these vesicles blood group antigens may be released both into the lume n and into the interstitial spaces.