Dietary n-3 PUFA suppress the Th2 type humoral response and enhance regulatory T cell numbers in a mouse model for cow's milk allergy

Introduction: Cow's milk allergy is the most common food allergy in children and no effective treatment is available to prevent or cure the disease. N-3 polyunsaturated fatty acids (n-3 PUFA) may prevent allergic disease. The aim of this study was to assess the effects of dietary supplementation with n-3 PUFA on the prevention of food allergy. Methods: C3H/HeOuJ mice were fed a 4% soybean oil/6% tuna oil diet rich in n-3 PUFA or a control diet (10% soybean oil) before and during oral sensitization with whey. Serum immunoglobulins and mouse mast cell protease-1 (mMCP-1), percentages (%) splenic Th1, Th2 and regulatory T cells (Treg) and the acute allergic skin response (ear swelling) were measured. Results: A strong reduction in whey-specific IgG1 levels in serum was observed in the n-3 PUFA diet group (Fig. 1), and IgE showed the same tendency. Hence, the Th2 type humoral response was suppressed. Furthermore, only mice fed the n-3 PUFA diet had a higher % Treg in spleen after sensitization as compared to sham sensitized mice (Fig. 2). In addition, both the % of Th1 and Th2 cells in the spleen were reduced; this effect was most pronounced in sham mice and resulted in an increased Th1/Th2 ratio. However, no effect of n-3 PUFA on mast cell degranulation was observed as assessed by acute allergic skin response and mMCP-1 measurements. Conclusion: Dietary n-3 PUFA prevented the induction of the Th2 type B cell response and enhanced Treg numbers in a murine model of food allergy; however the allergic effector response was not suppressed. (Figure presented).