Adhesion to intestinal epithelial cells is considered important for immune modulation, pathogen exclusion and prolonged residence time in the GIT. Viability of the probiotic strain is assumed to be important and metabolic activity may be pivotal for
the expression of anti-pathogenic activity. However, there is increasing evidence that bacterial compounds such as
DNA (some CpG motifs) or cell-wall fragments and ⁄ or dead bacteria can elicit certain immune responses