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Failure to induce oral tolerance in mice is predictive of dietary allergenic potency among foods iwth sensitizing capacity
Citation:
BOWMAN, C. AND M. K. SELGRADE. Failure to induce oral tolerance in mice is predictive of dietary allergenic potency among foods iwth sensitizing capacity. TOXICOLOGICAL SCIENCES. Society of Toxicology, RESTON, VA, 106(2):435-43, (2008).
Impact/Purpose:
The manuscript describes development of oral tolerance in a mouse model designed to assess potential allergenicity of genetically modified food crops. Results indicate that foods causing persistent allergy (peanut, Brazil nut) do not induce oral tolerance like ova or egg white do, and thus pose more of an allergenic risk. Highly digestible foods also lack tolerizing potential, but are not orally sensitizing either and thus pose little to no risk. The study was performed to develop tools for assessing potential allergenicity of genetically modified food crops.
Description:
Background: Food allergy likely results from a lack of oral tolerance, which specifically inhibits production of allergic IgE antibody. Some food allergies, such as egg allergy, are frequently outgrown, whereas other foods, such as peanuts and tree nuts, are associated with persistent allergic disease. Objective: We hypothesized that foods associated with persistent and severe allergy (peanut and Brazil nut) are less orally tolerizing than non-allergens (turkey and spinach) or foods associated with frequently resolving allergy (egg white) in a mouse model, and sought to examine digestibility and solubility as influential factors. Methods: Adult C3H/HeJ mice were exposed orally to food extracts and subsequently challenged with the same extract intraperitoneally. Induction of antigen-specific serum IgE relative to appropriate controls was used to indicate lack of tolerance. Digestibility was assessed in vitro, and pH alterations or encapsulation were used to modify solubility or digestibility. Results: Peanut, Brazil nut, turkey, and spinach did not induce oral tolerance in mice under the same conditions as ovalbumin and egg white. Egg white, peanut, and Brazil nut contain digestion resistant proteins, whereas turkey and spinach do not. Limiting digestion or increasing solubility with sodium bicarbonate enhanced oral tolerance to peanut and Brazil nut. Conclusion: Foods differ in their ability to induce oral tolerance, and this may explain why some allergies are more severe or persistent than others. However, the ability to induce oral tolerance can be altered by manipulating solubility or digestive lability, indicating that the conditions under which the allergen is encountered may impact disease development
