Transcriptional regulation of the mucosal IgA system

Secretory IgA is the major antibody class in the external body fluids of humans and is generated when secretory epithelial cells actively export locally produced dimers of IgA. Several unique defense functions needed for mucosal homeostasis and protection against pathogens are provided by secretory immunity. Although the remarkable drive of mucosal plasma cells for production of IgA dimers remains enigmatic, it is known that transcriptional activation of the IgA germline genes and J-chain gene is required. The epithelial capacity for IgA export is likewise regulated by transcriptional modulation of the level of polymeric Ig receptor. Therefore, transcriptional gene regulation in two different cell types is central for IgA-dependent mucosal immunity.