Defensins (alpha and beta) are cationic peptides with a broad spectrum of antimicrobial activity that comprise an important arm of the innate immune system. The a-defensins are distinguished from the beta-defensins by the pairing of their three disulfide bonds. To date, four human beta-defensins have been identified, BD-1, BD-2, BD-3 and BD-4. beta-defensins are expressed on some leukocytes and at epithelial surfaces. In addition to their direct antimicrobial activities, they are chemoattractant towards immature dendritic cells and memory T cells. Alternative Names: BD-2, BD 2 protein, BD-2 protein, SAP1 protein, BD2, Skin-antimicrobial peptide 1 protein, BD 2 protein, BD 2, BD-2 protein