Commensal bacteria protect against food allergen sensitization

Andrew T. Stefka, Taylor Feehley, Prabhanshu Tripathia, Ju Qiub, Kathy McCoyc, Sarkis K. Mazmaniand, Melissa Y. Tjotae, Goo-Young Seoa, Severine Caoa, Betty R. Theriaultf, Dionysios A. Antonopoulose, Liang Zhou, Eugene B. Change, Yang-Xin Fua, and Cathryn R. Naglera

PNAS September 9, 2014 vol. 111 no. 36 13145-13150

Speaker: Yang Fei(費暘)                                         Time: 14:00~15:00, Dec. 31, 2014

Commentator: Dr. Jiu-Yao Wang (王志堯老師)      Place: Room 601

Abstract:

Sensitization to foods most likely occurs in infancy or early childhood, but it can also occur in susceptible individuals throughout life. It has been suggested previously that the commensal microbiota may be associated with the increasing prevalence of food allergy. In addition, alterations in the composition of the intestinal microbiota induced by environmental factors (e.g.antibiotics, diet and sanitation) may play a central role in the regulation of allergic sensitization. In this study, it was demonstrated that both the antigen-specific tolerance and Clostridia-induced alteration of intestinal barrier permeability were required to prevent sensitization to food antigens. By using a sensitive capture ELISA method to measure the antigen concentration, the authors showed that Clostridia, which predominantly colonize the murine colon, could reduce the concentrations of allergens given by force feeding in mouse serum. They further found that Clostridiainduced early innate IL-22 production by RORγt⁺ innate lymphoid cells and T cells. The elevated IL-22 level in turn resulted in increased mucin production by the Goblet cells and, consequently,reduced the access of allergen to the bloodstream by decreasing the intestinal permeability to dietary proteins. The authors also confirmed that Clostridia induced expansion of the intestinal Tregcompartment and immunoglobulin class switching to IgA to reinforce the immunoregulatory environment required for tolerance to dietary antigens. In conclusion, the results demonstrate that mucosa-associated Clostridia play a critical role in protecting against sensitization to food allergens.

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