The oral delivery of the Brucella unlipidated protein U-OMP-16 abrogates the IgE-mediated milk allergy

SMALDINI PAOLA; IBAÑEZ A; FOSSATI ALBERTO; CASSATARO JULIANA; DOCENA GUILLERMO H.

Human Vaccines & Immunotherapeutics

Austin, Tex. : Landes Bioscience

Año: 2014

2164-5515

Food allergies are increasingly common disorders and no therapeutic strategies are yet approved. U-Omp16 is the outer membrane protein of 16 kDa from B. abortus and possesses a mucosal adjuvant property. In this study, we aimed to examine the U-Omp16 capacity to abrogate an allergen-specific Th2 immune response when it is administered as an oral adjuvant in a mouse model of food allergy. Balb/c mice were sensitized with cholera toxin and cow?s milk proteins (CMP) by gavage and simultaneously treated with U-Omp16 and CMP. Oral challenge with CMP was performed to evaluate the allergic status of mice. Symptoms, local (small bowel cytokine and transcription factor gene expression) and systemic (specific isotypes and spleen cell-secreted cytokines) parameters, and skin tests were done to evaluate the immune response. We found that the oral administration of U-Omp16 with CMP during sensitization, dampened the allergic symptoms, with negativization of immediate skin test and increased skin DTH response. Serum specific IgE and IL-5 were inhibited and a Th1 response was promoted (specific IgG2a antibodies and CMP-induced IFN-g secretion). We found at the mucosal site an inhibition of the gene expression corresponding to IL-13 and Gata-3, with an induction of IFN-g and T-bet. These results indicated that the oral administration of U-Omp 16 significantly controlled the allergic response in sensitized mice with a shift of the balance of Th1- and Th2-T cells towards Th1 predominance. These findings suggest that U-Omp 16 may be useful as a Th1-directing adjuvant in an oral vaccine.