Fig. 3.

Schematic representation of the epithelium present in the mucosal-associated lymphoid tissue (MALT) and the common mucosal immune system (CMIS). Particulate antigens are endocytosed by the M cells that transfer the antigens to the underlying lymphoid tissue where they are processed by macrophages and DCs. Antigen-activated lymphocytes will migrate via the regional lymph nodes, thoracic duct and the blood stream to the lamina propria of other mucosal effector sites and induce IgA production at the mucosal surfaces.