PANCREATIC DUCT INFLAMMATORY INFILTRATION IN THE NONOBESE DIABETIC (NOD) MOUSE

The pancreatic duct system during the early stages of type 1 diabetes was examined in 8-wk-old female nonobese diabetic (NOD) mice. Infiltra tion was seen to involve the smaller ducts while the larger ducts were usually free from ductulitis. The infiltration affected ducts both cl ose to and remote from the islets of Langerhans. In the former situati on, infiltration of the islet and that of the duct were not separable. A strong positivity for both Ia and ICAM-1 molecules was observed in all infiltrated ducts, indicating that this infiltrating process is du e to the same elements as are involved in the islet inflammation and t hat also mononuclear cells infiltrating the nonislet ducts express adh esive mechanisms. At the ultrastructural level, endocrine cells that w ere mainly of the 'closed' type were observed intermingled with the du ctular epithelial cells and infiltrating mononuclear cells were detect ed either in the connective layer or among the epithelial cells of the affected ducts.