Intestinal anaphylaxis in the rat as a model of food allergy.

An animal model of food allergy has been developed in which some aspects of the allergic response could be quantified and the effects of various drugs evaluated. The change in permeability of the intestinal tract of actively sensitized rats, after oral challenge with the sensitizing antigen, was the parameter measured. Rats were sensitized by injection of egg albumin and B. pertussis vaccine to induce reaginic antibody to egg albumin. Two weeks after sensitization, 125I-labelled bovine serum albumin (125I-labelled BSA) was injected intravenously, followed by oral challenge with egg albumin. Pieces of intestinal tissue were obtained and the amount of 125I-labelled BSA determined in a gamma counter. The amount of 125I-labelled BSA in the intestinal tissue of sensitized and challenged rats regularly showed an increase of greater than 100% above values for control rats.