Experimental allergic pancreatitis was induced in rats and guinea pigs by immunization with rat or guinea pig pancreas tissue emulsified in complete Freund's adjuvant containing 1 mg/ml Mycobacterium tuberculosis and also by injection of pertussis vaccine.
By light microscopy, the lesion was characterized by in filtration of mononuclear cells in the periductal and perivascular area and also in the acinar tissue accompanied by the cellular necrosis and edema. However, no inflammatory lesion was found in Langerhans' islets. Development of the pancreatitis was observed at 10th day to 14th day after one shot immunization. On the contrary, no pathological abnormality was found in the pancreas of the animals received multiple immunization (6 times) with the pancreatic antigen.
The sera of animals with the pancreatitis showed neither precipitating antibody, nor antibody fixing against frozen pancreatic sections detected by using the method of indirect immunofluorescence. The sera of animals received the multiple immunization with the pancreatic antigen showed the precipitating antibody against the pancreatic antigen. In addition, the sera showed the antibody fixing to cell membrane and cytoplasm of the pancreatic acinar (not to Langerhans' islets) detected by indirect immunofluorescence. The precipitating antibody was not absorbed with rat erythrocytes, liver, and serum. The antibody fixing with pancreatic tubular cells of rat did not react with the frozen pancreatic sections obtained from human, dog and rabbit.
On the laboratory test, blood sugar level remained within normal range, however, the level of serum amylase was increased in some guinea pigs at 7th day after the immunization with pancreas of rat.
These results suggested that the pancreatitis was developed not by humoral antibody, but by cellular immunity. The experimental allergic pancreatitis in rats and guinea pigs will be good model to elucidate the pathogenesis of human pancreatitis induced due to unk-nown causes.
