IKKβ in intestinal epithelial cells regulates allergen-specific IgA and allergic inflammation at distant mucosal sites

Regulation of allergy responses by intestinal epithelial cells remain poorly understood. Using a model of oral allergen sensitization in the presence of cholera toxin as adjuvant and mice with cell-specific deletion of IKKβ in intestinal epithelial cells IECs (IKKβ(ΔIEC)), we addressed the contribution of IECs to allergic sensitization to ingested antigens and allergic manifestations at distant mucosal site of the airways. Cholera toxin induced higher proinflammatory responses and altered the profile of the gut microbiota in IKKβ(ΔIEC) mice. Antigen-specific IgE responses were unaltered in IKKβ(ΔIEC) mice, but their IgA Abs, Th1 and Th17 responses were enhanced. Upon nasal antigen challenge, these mice developed lower levels of allergic lung inflammation, which correlated with higher levels of IgA Abs in the airways. The IKKβ(ΔIEC) mice also recruited a higher number of gut-sensitized T cells in the airways after nasal antigen challenge and developed airway hyper-responsiveness, which were suppressed by treatment with anti-IL-17A. Fecal microbiota transplant during allergic sensitization reduced Th17 responses in IKKβ(ΔIEC) mice, but did not affect IgA Ab responses. In summary, we show that IKKβ in IECs shapes the gut microbiota and immune responses to ingested antigens and influences allergic responses in the airways via regulation of IgA Ab responses.