Defensins and Host Defense

Defensins are antimicrobial peptides produced by cells as part of the host9s immune defense system against invading pathogens. A Perspective by Tomas Ganz highlights three papers that provide new insights into the structure and function of vertebrate defensins. In mice, a-defensins produced by the Paneth cells of the small intestine help defend the host against invasion by intestinal pathogens such as Escherichia coli and Salmonella ( Wilson et al.). Two human b-defensins have been shown to act as chemoattractants for dendritic cells and memory T cells ( Yang et al.), and a new cyclic q-defensin identified in monkeys has powerful antimicrobial activity and may be a molecular template for designing new antibiotics ( Tang et al.).