Figure 4.

Sampling by dendritic cells (DC) of antigens in the intestinal lumen. At least four pathways have been described by which DC can acquire gut antigens: (1) following transport of antigens by M cells; (2) by reaching between epithelial cells directly into the lumen; (3) via the epithelium, either by uptake of material transported by epithelial cells or following uptake of apoptotic epithelial cells; and (4) by direct access to antigens as a result of breaks in the integrity of the epithelium.