Leukocyte antimicrobial peptides: multifunctional effector molecules of innate immunity

Antimicrobial peptides are effector molecules of innate immunity that provi de a first line of defense against pathogens, In mammals, they are stored i n granules of leukocytes and are present in those sites that are exposed to microbial invasion, such as mucosal surfaces and skin. In the last decade, biochemical investigations and recombinant DNA technology have allowed the identification and characterization of several antimicrobial peptides from various animal and vegetal species. Most of the mammalian peptides have be en grouped in two broad families: defensins and cathelicidin-derived-peptid es, Functional studies have shown that the toxicity mechanisms for many pep tides consist of a rapid permeabilization of the target cell membrane, In a ddition to their microbicidal activity, some members of both families are m ultifunctional molecules, playing a modulating role in the inflammation and the antigen-driven immune response.