title: NK-lysin and its shortened analog NK-2 exhibit potent activities against Trypanosoma cruzi.
abstract: Antimicrobial peptides are widespread in nature and have been evolutionarily conserved as essential tools for combating a variety of pathogens. Among the plethora of natural peptides and synthetic analogs thereof studied in recent years for their antimicrobial activities, only a very few are known to be effective against protozoan parasites. In the present study we investigated the activity of NK-lysin, a broad-spectrum effector polypeptide of mammalian cytotoxic lymphocytes, against trypomastigotes of the human pathogen Trypanosoma cruzi in vitro. Moreover, the activity of a synthetic peptide named NK-2 that corresponds to the cationic core region of NK-lysin was tested in parallel against this parasite. T. cruzi was found to be highly susceptible to both peptides, as evidenced by inhibition of the mobility of trypomastigotes. The peptides rapidly permeabilized the plasma membrane of the parasite since micromolar concentrations resulted in the release of cytosolic enzymes within minutes. NK-lysin and NK-2 were even found to kill trypanosomes residing inside the human glioblastoma cell line 86HG39, but only NK-2 left the host cells apparently unharmed.
authors.affiliation: Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany. tjacobs@bni.uni-hamburg.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Jacobs
authors.forename: Heike
authors.initials: H
authors.lastname: Bruhn
authors.forename: Iris
authors.initials: I
authors.lastname: Gaworski
authors.forename: Bernhard
authors.initials: B
authors.lastname: Fleischer
authors.forename: Matthias
authors.initials: M
authors.lastname: Leippe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000302:isolation & purification / Q000494:pharmacology*; D010455:Peptides / Q000302:isolation & purification / Q000494:pharmacology*; D011510:Proteolipids / Q000494:pharmacology*; D011663:Pulmonary Surfactants / Q000494:pharmacology*; D014349:Trypanosoma cruzi / Q000187:drug effects*
chemical_list: D000890:Anti-Infective Agents; C093238:NK-lysin; D010455:Peptides; D011510:Proteolipids; D011663:Pulmonary Surfactants; C475945:peptide NK-2