Comparison of antibody responses to hen's egg and cow's milk proteins in orally sensitized rats and food-allergic patients

Background: No adequate enteral sensitization models are available to study food allergy and the allergenicity of food proteins. To further validate a n enteral brown Norway (BN) rat sensitization model under development, we s tudied specific protein recognition to determine whether a comparable patte rn of proteins is recognized by the rat immune system and the human immune system. Methods: The animals were exposed to either ovalbumin as a positive referen ce control, hen's egg-white-protein extract, or a cow's milk preparation by daily gavage dosing (0.5, 1, 2.5, 5, 10, or 15 mg protein per rat/day) for 9 weeks. No adjuvants were used during the sensitization studies. The spec ificities of antibodies against hen's egg-white proteins or cow's-milk prot eins in sera from orally sensitized rats and food-allergic patients were st udied and compared by immunoblotting. Results: The IgG and IgE antibodies to hen's egg-white proteins and cow's-m ilk proteins present in sera from orally sensitized rats and food-allergic patients showed a comparable pattern of protein recognition. Conclusions: Upon daily intragastric exposure to food allergens, the specif icities of the induced antibody responses in the BN rat resemble those foun d in food-allergic patients. These studies add further support to the hypot hesis that the BN rat may provide a suitable animal model for food allergy research and research on the allergenicity of food proteins.