Figure 5: Interaction between gut microbiota and the mucosal immune system. Cellular processes depicted in the hatched circles 1, 2, and 3, are explained in the text. Cells of the mucosal immune system are indicated as follows: dendritic cell (DC), undifferentiated T helper lymphocyte (Th0), regulatory T helper lymphocyte (Treg), type 17 T helper lymphocytes (Th17), type 3 innate lymphoid cell (ILC3), and B lymphocyte (B cell).