Sampling of the intestinal microbiota by epithelial M cells.

Sampling of intestinal pathogens and commensals is an important aspect of the gut immune system, and is accomplished through the action of specialized epithelial M cells. Although their sampling abilities have been appreciated for decades, few molecular details of their development or function are known. This review discusses several recent advances in our understanding of these cells, including signals controlling their development, the mechanisms they use for taking up microbes, and their exploitation by certain pathogens. Future research directions are discussed, including development of oral vaccines.