Cysteine-rich antimicrobial peptides in invertebrates

Antimicrobial peptides are pivotal elements of the innate immune defense ag ainst bacterial and fungal infections. Within the impressive list of antimi cirobial peptides available at present, more than half have been characteri zed in arthropods. Cysteine-rich antimicrobial peptides represent the most diverse and widely distributed family among arthropods and, to a larger ext ent among invertebrates. Proeminent groups of cysteine-rich peptides are pe ptides with the CS alpha beta motif and peptides forming an hairpin-like P- sheet structure. Although these substances exhibit a large structural diver sity and a wide spectrum of activity, they have in common the ability to pe rmeabilize microbial cytoplasmic membranes. Drosophila has proved a remarka ble systemfor the analysis of the regulation of expression of gene encoding antimirobial cysteine-rich peptides. These studies have unraveled the stri king parallels that exist between insect immunity; and innate immunity in m ammals that point to a common ancestry of essential aspects of innate immun ity. (C) 1999 John Wiley & Sons, Inc.