An adjuvant-free mouse model to evaluate the allergenicity of milk whey protein.

Milk allergy is the most common type of food allergy in humans with the potential for fatality. An adjuvant-free mouse model would be highly desirable as a preclinical research tool to develop novel hypoallergenic or nonallergenic milk products. Here we describe an adjuvant-free mouse model of milk allergy that uses transdermal sensitization followed by oral challenge with milk protein. Groups of BALB/c mice were exposed to milk whey protein via a transdermal route, without adjuvant. Systemic IgG1 and IgE antibody responses to transdermal exposure as well as systemic anaphylaxis and hypothermia response to oral protein challenge were studied. Transdermal exposure resulted in a time- and dose-dependent induction of significant IgE and IgG1 antibody responses. Furthermore, oral challenge of sensitized mice resulted in significant clinical symptoms of systemic anaphylaxis within 1 h and significant hypothermia at 30 min postchallenge. To study the underlying mechanism, we examined allergen-driven spleen cell T-helper 2 cytokine (IL-4) responses. There was a robust dose- and time-dependent activation of memory IL-4 responses in allergic mice but not in healthy control mice. These data demonstrate for the first time a novel transdermal sensitization followed by oral challenge mouse model of milk allergy that does not use adjuvant. It is expected that this model may be used not only to study mechanisms of milk allergy, but also to evaluate novel milk products for allergenic potential and aid in the production of hypo- or nonallergenic milk products.