936 GUT INDUCED ANAPHYLAXIS AND UPTAKE OF A BYSTANDER PROTEIN: AN AMPLIFICATION OF ANAPHYLACTIC SENSITIVITY

Abstract

This study sought to test the effect of intestinal anaphylaxis on uptake of an unrelated antigen. Adult rats were immunized with 100 ug egg albumin (EA) and alum. Fourteen days later, intestinal anaphylaxis was induced by intraduodenal or intragastric challenge with EA. To test for the changes in vascular and mucosal permeability with anaphylaxis, rats were given 125I-RSA intravenously on challenge and the radioactivity retained in the wall of the gut segments and the trichloracetic acid (TCA)-precipitable radioactivity present in secretions from these segments was determined. Enhanced retention of 125I-RSA was found in the wall of the gut segments and increased amounts of TCA-precipitable radioactivity was found in secretions from antigen-challenge compared to control rats. In other EA immunized rats, bovine serum albumin (BSA) was administered by gavage one hour before challenge with EA. Increased amounts of immunoreactive BSA was detected by radioimmunoassay in serum of rats subjected to local intestinal anaphylaxis. Among the consequences of enhanced systemic uptake of protein present during intestinal anaphylaxis is the induction of an IgE antibody response to this protein. Preliminary experiments suggest that an IgE antibody response can be induced by this mechanism. These findings suggest the broadening of anaphylactic sensitivity of animals to new antigens and may explain multiple sensitivities to food antigens in humans.