Methods: Female C3H/HeOuJ mice (n=8 per group) were orally exposed to DON plus whey once a week for 5 weeks, while control mice received DON in PBS. Acute allergic skin responses, change in body temperature and other anaphylactic shock reactions were measured upon whey-challenge. Allergen-specific antibodies and ST2 were measured in serum. mRNA expression of claudin-2 and -3, E-cadherin and IL-33 were determined in intestinal tissue and ST2 was measured in serum 6h after a single oral DON-exposure.
Results: Mice exposed to DON plus whey showed whey-specific IgG1, IgG2a and IgE antibodies in serum and an acute allergic skin response upon intradermal whey challenge compared to control mice. Furthermore, a significant time-dependent increase in soluble ST2 in serum was observed in DON plus whey sensitized mice compared to control mice. In addition, analysis of intestinal tissues, isolated 6h after a single oral exposure to DON, revealed increased mRNA expression of the tight junction proteins claudin-2 and -3 and the adherens junction E-cadherin, as well as an increase in IL-33 mRNA accompanied by an increase in the soluble IL-33 receptor ST2 in serum.
Conclusions: Together, these results demonstrate that DON facilitates allergic sensitization and may thus serve as a model adjuvant. Our data therefore illustrate the possible contribution of food contaminants, like DON, in allergic sensitization in humans.