Role of defensins in innate immunity

Immune system of living organisms ranging from fungi, plants, vertebrates and invertebrates are all aided by polypeptide chains like defensins and cathelicidins. In humans the defensisns are quite fundamental part of innate immune system in combating with day-to-day exposure to unknown pathogens. The defensins are classified as alpha beta and sigma defensins expressed at chromosome 8 at nearly same positions, the sigma defensin is however synthetically developed as reterocyclin, as it has been stopped producing because of evolutionary development of stop codon 7.5 million years ago. The expression of Defensins can be either constitutive or inducible through epithelial cells, Paneth cells or other respective immune cells to regulate the activation of the innate immune responses. These impart their role either by direct microbicidal action, antiviral activity, inactivation or neutralization of microbial products, mobilization or activation of phagocytes and mast cells. Further to this there is lot more to explore about the availability of similar genetic expressions as defensins with unclear functions and in vivo experimental models development.