Among food allergies, peanut allergy is frequently associated with severe anaphylactic reactions. In the need for safe and effective therapeutic strategies, probiotics may be considered on the basis of their immunomodulatory properties. The aim of the present study was to investigate the immunological mediators involved in the effects of probiotic VSL#3 oral supplementation on Th2 inflammation and anaphylaxis in a mouse model of peanut allergy.

VSL#3 supplementation to peanut‐sensitized mice was effective in ameliorating anaphylaxis and Th2‐mediated inflammation, by promoting regulatory responses in the jejunum mucosa and in the mesenteric lymph node, as evaluated by ELISA, real‐time PCR, histologic, and immunohistochemical analysis. Probiotic‐induced TGF‐β mediates its protective effects through the induction of regulatory T cells expressing FOXP3 and/or latency‐associated peptide, as proven by in vivo blockade of TGF‐β in VSL#3‐treated mice with a neutralizing monoclonal antibody one day before challenge.

TGF‐β, induced in the gut by VSL#3 supplementation, is capable of reducing the Th2 inflammation associated with food anaphylaxis in a mouse model of peanut sensitization. TGF‐β acts through the induction/maintenance of regulatory T cells expressing FOXP3 and/or latency‐associated peptide. Probiotics supplementation may represent an effective and safe strategy for treating food allergies in adult population.