Candidacidal activity of shortened synthetic analogs of amoebapores and NK-lysin.

Natural antimicrobial peptides and synthetic analogs thereof have emerged as compounds with potentially significant therapeutical application against human pathogens. Amoebapores are 77-residue peptides with cytolytic and antibacterial activity considered to act by forming ion channels in cytoplasmic membranes of the victim cells. A functionally and structurally similar peptide named NK-lysin exists in mammalian lymphocytes. Several synthetic analogs of amoebapores and NK-lysin, which are substantially reduced in size compared to the parent molecules, were tested for their ability to inhibit the growth of and to kill Candida albicans. Some of the peptides displayed potent activity against a clinical isolate as well as against defined culture strains. Among the most active peptides found are some shortened substitution analogs of amoebapore C and a cationic core region of NK-lysin. As these peptides are also highly active against Gram-positive and Gram-negative bacteria but are of low cytotoxicity towards a human keratinocyte cell line they may provide promising templates for the design of broad-spectrum peptide antibiotics.