Induction of food allergy in PI3K-deficient mice.

<p>PI3K^−/− mice as a gastrointestinal mast cell-deficient murine model were subjected to FA-inducing oral OVA challenges. <i>A</i>: The occurrence of allergic diarrhea in WT mice (WT FA mice) and PI3K^−/− mice (PI3K^−/− FA mice) after each oral OVA challenge is shown (<i>n</i> = 5 mice per group). <i>B</i>: The proximal colon of FA-induced PI3K^−/− mice after oral OVA challenge was stained with anti- mMCP-1 antibodies. Scale bars represent 200 µm. <i>C</i>: The level of mMCP-1 in the plasma of PI3K^−/− naïve mice and PI3K^−/− FA mice is shown. The level of mMCP-1 in the plasma was determined using an ELISA kit. Data are expressed as means ±SE. **<i>P</i><0.01 vs. WT naïve mice, ††<i>P</i><0.01 vs. WT FA mice (<i>n</i> = 3–5 mice per group). IL-4 and IL-5 cytokine mRNA expression in the spleen (<i>D</i>) and proximal colon (<i>E</i>) from WT naïve mice, WT FA mice, PI3K^−/− naïve mice and PI3K^−/− FA mice were measured by real-time PCR. Relative mRNA levels of cytokines were normalized to GAPDH expression. *<i>P</i><0.05, **<i>P</i><0.01 vs. each naïve mice, ††<i>P</i><0.01 vs. WT FA mice (<i>n</i> = 4–7 mice per group).