The multifaceted activities of mammalian defensins

Defensins are an important family of cationic and cysteine-rich host defense peptides that are widely distributed in plants, fungi, and animals. In mammals, defensins exert potent antimicrobial and immunomodulatory activities linking the innate and adaptive immune responses. These peptides play critical roles in health and disease as defects in their production are associated with abnormal host responses to infection, chronic inflammatory diseases, and cancer. There is much interest in elucidating the structure-function relation and modes of action of the defensins to better understand how these peptides kill microbes and regulate the host immune responses. Such knowledge is expected to help in the design of novel defensin-based therapeutics. This review focuses on the multifaceted antimicrobial and immunomodulatory activities of human and murine defensins.