Oral administration of Escherichia coli Nissle 1917 prevents allergen-induced dermatitis in mice

Background: The prevalence of allergies has been linked to Western life style factors including a decrease of microbial exposure. Probiotics, such as Escherichia coli Nissle 1917 (EcN), have been shown to be beneficial for prevention and treatment of several chronic inflammatory diseases. Objective: The aim of this study was to investigate the impact of oral EcN administration on development and outcome of allergen-induced dermatitis. Methods: In sensitized BALB/c mice, skin inflammation was induced by topical allergen application. EcN was administered orally in a preventive manner. Severity of dermatitis was analysed by evaluation of skin score, local cellular and cytokine profile. The systemic immune response was assessed by analysis of immunoglobulins and allergen-dependent cytokine response. Results: Oral EcN administration improved allergen-induced dermatitis dose-dependently. In parallel, a reduction of epidermal thickness and infiltrating immune cells together with an enhanced number of forkhead box P3 (Foxp3)(+) cells and a trend of increased IFN gamma, IL-10 and TGF beta expression was detected in eczematous skin. In allergen-stimulated splenocytes reduced IL-4 and IFN gamma along with an elevated IL-10 production and a tendency to an increased TGF beta secretion were observed. Conclusions: Our findings indicate that EcN alters the local allergen-induced immune response by increase of Foxp3(+) cells and by favouring an immunoregulatory cytokine pattern. Thus, oral administration of EcN might be an effective strategy in prevention and potentially therapy of allergic inflammatory skin diseases.