Specific antigen exclusion and non-specific facilitation of antigen entry across the gut in rats allergic to food proteins.

The intestinal absorption of ovalbumin and beta-lactoglobulin was measured in Hooded Lister rats which had previously been made allergic to ovalbumin, and in unimmunized controls. The antigens were introduced both together and separately into closed intestinal loops. Absorption of free ovalbumin, but not beta-lactoglobulin, was reduced in rats with anti-ovalbumin antibody, demonstrating antigen-specific immune exclusion despite the presence of reaginic antibody. In contrast, the absorption of beta-lactoglobulin was enhanced by the presence of ovalbumin in rats with IgE anti-ovalbumin, but not in unimmunized controls. These results suggest that macromolecular absorption may be increased in an antigen non-specific way in food allergy.