Mucosal B cells

Mucosal B cells are crucial for host defense. The mucosal surfaces exceed 300 m2 in humans and represent indeed the largest part of the body in which immune responses take place daily. Mucosal B cells, located in the gut, respiratory, and urogenital mucosae as well as in skin, salivary, mammary, and lacrimal glands, are very important to protect ourselves from infections. Most harmful pathogens enter the body through the mucosal surfaces by ingestion, inhalation, or sexual contact. This chapter focuses on the mechanisms that coordinate B-cell development as well as on the mechanisms used by mucosal B cells and mucosal IgA to give protection to the host.