Combined exposure of intestinal epithelial cells to the dietary oligosaccharide mixture ScFOS/LcFOS and CpG DNA enhances the Th1 and regulatory IL-10 response in an allergen-specific co-culture model

Introduction: The intestinal mucosa plays a key role in the development of food allergies. We studied the interaction between intestinal epithelial cells (IECs) and PBMCs of peanut-allergic patients in a transwell co-culture model. Exposure of IECs to a mixture of galacto-and/or long chain fructo-oligosaccharides (scGOS/lcFOS) in combination with synthetic CpG DNA (TLR9 ligand),modulated the cytokine response of activated PBMCs, driving away from the allergic phenotype. Objectives: Our aim was to compare the efficacy of scGOS/lcFOS with a scFOS/lcFOS mixture and to evaluate these effects in an allergen-specific co-culture model. IECs (HT-29, human colon adenocarcinoma) were grown on transwell filters until confluence. IECs were apically exposed to 0.5% 9:1 scGOS/lcFOS or scFOS/lcFOS either or not in combination with 2.5 μmol L-1 CpG DNA to mimic presence of DNA of beneficial bacterial in the gut. These IECs were co-cultured with basolateral PBMCs from peanut-allergic patients, either activated with anti-CD3/CD28 (24 hours) or peanut-extract (PE, 6 days).Cytokines IFN-γ, IL-10, IL-13 and TNF-a were measured in the basolateral supernatant and T-cell polarization of the PBMCs was determined (Th2, Th1, Treg and Tfh). Results: Apical exposure of IECs to CpG DNA increased basolateral IFN-γ and IL-10 production by anti-CD3/CD28 activated PBMCs (P