Current Status of Defensins and their role in the Oral Cavity

The discovery of widespread distribution of antimicrobial peptides over the past 20 years has provided insight into the innate defensive system that permits multicellular organisms, including humans, to live in harmony with microbes. Among the innate mechanism that aims to establish a regulated equilibrium between health and disease, natural antimicrobial peptides, especially those part of defensins family, have emerged as fundamental mediators. Defensins are endogenous, small, cysteine-rich antimicrobial peptides that are produced by leukocytes and epithelial cells. Substantial evidence accumulated in recent years indicates that mammalian defensins are multifunctional and, by interacting with host cell receptor(s), participate in both the innate and adaptive antimicrobial immunity of the host, though their participation in host adaptive, anti-microbial immunity has just begun to unfold. Oral cavity has a unique environment in which epithelia are constantly exposed to a variety of microbial challenges. Secretion of β-defensins from oral epithelium and the constant influx of neutrophil α-defensins along with other salivary defense molecules serve as an efficient barrier against the formation of a pathogenic sub-gingival plaque or biofilm. Present review focuses on the current status of defensins’ classification, strucuture, expression and their role in oral environment.