In Situ Ultrastructural Demonstration of Cells Bearing la Antigens in the Murine Pancreas

Although an important role has been postulated for class II major histocompatibility gene products in the rejection of transplanted islets, the identity of the cells bearing these molecules within pancreatic tissue has been the topic of some controversy. To clearly define the cell population(s) within the murine pancreas that express la antigens, perfused murine pancreata were processed for the ultrastructural in situ demonstration of la antigens. It was found that la antigen expression was restricted to mononuclear cells adjacent to capillaries throughout the exocrine and endocrine portions of the pancreas. Vascular endothelium and ductular epithelium did not express detectable amounts of la antigens.