This is an endogenous antibiotic peptide and monocyte chemotactic peptide produced by human neutrophils. Defensins are a family of 3-4 kDa (29-34 amino acids) peptides found in the granules of mammalian phagocytes. The members of this famuly are variably arginine-rich and all share 6 conserved cysteine residues th at participate in intramolecular disulfide bonds.