Intestinal uptake of macromolecules. IV.--The effect of pancreatic duct ligation on the breakdown of antigen and antigen-antibody complexes on the intestinal surface.

We have previously shown a consistent decrease in antigen absorption in vitro by ileal and jejunal gut sacs from orally or parenterally immunized rats in contrast to controls. In immunized rats, antigen appeared to be retained on the surface of the intestine and to be retained on the surface of the intestine and to undergo enhanced degradation by local proteases. This study was concerned with the role of pancreatic enzymes in degradation of antigen and antigen-antibody complexes. The breakdown of [125I]bovine serum albumin (BSA) by jejunal and ileal gut sacs from BSA-immunized, pancreatic duct-ligated rats was significantly decreased in comparison to that of BSA-immunized, sham-operated controls. Treatment of the immunized, pancreatic duct-ligated rats with pancreatic extracts prior to removal of the gut sacs, led to an increase in breakdown of [125I]BSA by the gut sacs in vitro. These findings suggest that pancreatic enzymes adsorbed to the surface of the intestine contribute to the proteolysis of antigens and antigen-antibody complexes at this site.