Immunomodulatory Effects of Lactobacillus casei Administration in a Mouse Model of Gliadin-Sensitive Enteropathy.

Coeliac disease (CD) is a very common food-sensitive enteropathy, which is triggered by gluten ingestion and is mediated by CD4+ T cells. In addition, alterations in the intestinal microbiota that is normally involved in the homeostasis of GALT (gut-associated lymphoid tissue) seem to play a role in CD. In accordance with these findings, we previously reported that L. casei can induce a strong enhancement of the T cell-mediated response to gliadin with- out inducing enteropathy. In this study, we analysed the effects of L. casei administration in a mouse model of gliadin-induced villous damage that was recently developed and involves the inhibition of cyclo-oxygenase (COX) activ- ities in gliadin-sensitized HLA-DQ8 transgenic mice. To address the issue, we assessed the weight loss, the intestinal cytokine pattern, the density of CD25+ cells and morphometry of the gut mucosa. We confirmed that COX inhibition in sensitized mice caused villus blunting, dysregulated expression of tumour necrosis factor (TNF)-a and reduced gliadin-specific IL-2 production. Notably, the administration of probiotic strain induced a complete recovery of villus blunting. This finding was associated with a delay in weight decrease and a recovery of basal TNF-a levels, whereas the numbers of CD25+ cells and the levels of IL-2 remained unchanged. In conclusion, our data suggest that the administration of L. casei can be effective in rescuing the normal mucosal architecture and GALT homeostasis in a mouse model of gliadin-induced enteropathy.