A) Experimental design (S: sensitization, C: challenge, PPI: proton pump inhibitor). B-E) Representative CAE-stained histological sections of small intestine from mice from each experimental group. F) Summary of average counts of mast cells per high power field. G) Serum concentrations of MCPT-1 at the experimental endpoint. H and I) Serum total and OVA-specific IgE concentrations at experimental endpoint. J-M) Expression of cytokine transcripts in the small intestines of mice from each experimental group at study endpoint. UT: Untreated, OM: Omeprazole, OVA: Ovalbumin. Data are shown are from one experiment representative of three independent experiments with n = 3–6 per group. Statistical analysis by one-way analysis of variance. *P<0.05, **P<0.01