Major histocompatibility complex antigens in the rat pancreas, isolated pancreatic islets, thyroid, and adrenal.

Monoclonal antibodies to rat class I and class II MHC antigens have been used with the peroxidase-antiperoxidase technique to localize these antigens in the DA rat pancreas, isolated pancreatic islets, adrenal, and thyroid tissue. The class I (RT1A) antigens were found to be expressed by pancreatic islet cells, adrenal cortical cells, thyroid follicular cells, and--in low concentration--on cells of the adrenal medulla. These same cells did not express class II (Ia or RT1B) antigens. However, interstitial dendritic cells, staining intensely for class II antigens were present in thyroid, adrenal and pancreatic tissue, and within isolated pancreatic islets. These cells probably represent the immunogenic passenger leukocyte.