Involvement of M cells in the bacterial invasion of Peyer's patches: a common mechanism shared by Yersinia enterocolitica and other enteroinvasive bacteria.

Recent evidence indicates that ileal Peyer's patches represent the main infection route for Yersinia enterocolitica. In this study transmission and scanning electron microscopy have shown that only a small fraction of bacteria present in the lumen adhere to the follicle-associated murine epithelium with no discernible preference for either M or absorptive cells. Yersiniae attached to M cells are phagocytosed and transported from the lumen into the lamina propria. No invasion of columnar absorptive cells was observed. These data, in combination with recently published reports, indicate that the involvement of M cells is a common step in bacterial invasion of Peyer's patches.