Host defense peptides and their antimicrobial-immunomodulatory duality.

Host defence peptides (HDPs) are short cationic molecules produced by the immune systems of most multicellular organisms and play a central role as effector molecules of innate immunity. Host defence peptides have a wide range of biological activities from direct killing of invading pathogens to modulation of immunity and other biological responses of the host. HDPs have important functions in multiple, clinically relevant disease processes and their imbalanced expression is associated with pathology in different organ systems and cell types. Furthermore, HDPs are now evaluated as model molecules for the development of novel natural antibiotics and immunoregulatory compounds. This review provides an overview of HDPs focused on their antimicrobial-immunomodulatory duality.