Acute allergic skin reactions and intestinal contractility changes in mice orally sensitized against casein or whey.

BACKGROUND

Cow's milk allergy (CMA) is characterized by hypersensitivity against casein or whey, affecting 2.5% of young infants. The pathogenesis of CMA involves IgE as well as non-IgE-mediated reactions and clinical symptoms are found in the skin, lungs and gastrointestinal tract. In this study, local and systemic immunopathology was determined in whey- or casein-allergic mice.

METHODS

Mice were orally sensitized with casein or whey using cholera toxin as an adjuvant. Serum immunoglobulins and the acute allergic skin reaction (ear swelling 1 h after intradermal allergen challenge) were determined to reveal systemic hypersensitivity. Furthermore, pathophysiological changes were assessed within the intestine.

RESULTS

An acute allergic skin reaction was induced in both whey- and casein-sensitized mice. In these mice, whey-specific IgE, IgG(1), IgG(2a) and casein-specific IgG(1) levels were found to be increased. In addition, the serum mouse mast cell protease-1 (mMCP-1) concentration was enhanced, reflecting mast cell degranulation. Indeed, the number of mMCP-1-positive mast cells within the colon was diminished in both whey- and casein-sensitized mice. Only in casein-sensitized mice isometric contraction of the colon was reduced, reflecting motility alterations.

CONCLUSIONS

Mice, orally sensitized against casein or whey, revealed an allergen-specific acute allergic skin reaction. In casein-sensitized mice, hypocontractility of the colon reflected pathophysiological changes within the intestine. Allergen-induced ear swelling and intestinal contractility changes are novel parameters in animal models of CMA which may add to the search for new therapeutic strategies to relieve symptoms of CMA.