Events at the host-microbial interface of the gastrointestinal tract. V. Paneth cell α-defensins in intestinal host defense

Host defense of the small intestine is mediated, in part, by antimicrobial peptides, including α-defensins. In the small intestine, Paneth cells, specialized secretory epithelial cells located at the base of the crypt invaginations lining the intestinal wall, produce α-defensins. The α-defensins are cysteine-rich cadonic peptides with antibiotic activity against a wide range of bacteria and other microbes. Studies of transgenic and knockout mice have supported a pivotal role of Paneth cell α-defensins in protection from bacterial pathogens. New data suggest that deficient expression of Paneth cell α-defensins may contribute to the pathophysiology of Crohn's disease, a chronic inflammatory bowel disease.