The intestinal mucosa is continuously challenged by innocuous antigens and potentially harmful pathogens. Therefore, the local immune system has to mount an efficient answer towards pathogenic bacteria but has to keep the immunological balance during exposure to commensal antigens. Dendritic cells (DC) are most likely involved within this dual functionality. DC from normal colonic mucosa and DC from mesenterial lymph nodes contain a significant subpopulation of CD103+ (Integrin αEβ7) DC, an adhesion molecule that also characterizes some T cells with regulatory function. During chronic intestinal inflammation αE-positive DC are lost from the gut. Therefore, we hypothesize that expression of the αE - integrin on the surface of mucosal DC defines a subgroup of DC that is involved within tolerance induction and maintenance. Aim of our study is to investigate the influence of intestinal αEβ7+ DC in the immunological homeostasis within the healthy gut and their involvement in the suppression of chronic inflammation.
