When murine BM-DC were incubated with various lactobacillus strains or their exopolysaccharides, we observed that the capacities of the cells/polymers to up-regulate the expressions of MHC class I and II and co-stimulatory (CD80, CD86, CD40) molecules differed greatly based on the IBD status of the mice from which the bacteria were isolated. This evidence concerns the gene CD40 and inflammatory bowel disease.