ABSTRACT
It is well known that the epidermis forms an effective structural barrier and is also highly resistant to pathological infection by the many different types of microorganism that colonize its surface. If the epidermal barrier is breached by pathogens, the first line of defence is the hosts innate immune response followed by the adaptive immune response. The innate immune response consists of a number of pre-existing defence mechanisms including phagocytic and natural killer cells, mast cells as well as epithelial cells themselves (1). These cells respond to microbial pathogens in a number of ways including the release of antimicrobial peptides. More than 500 antimicrobial peptides have been described in plants, insects, amphibians, and mammals, with broad-spectrum activity against bacteria, fungi, and viruses, representing an integral part of innate immunity (2,3). Of these antimicrobial peptides, the defensins, adrenomedullin (AM), and cathelicidins are perhaps the most widely studied in skin, although to date only defensins and AM appear to have been investigated in acne.
