Parasiticidal activity of a novel synthetic peptide from the core α-helical region of NK-lysin.

Abstract

NK-lysin is an anti-microbial peptide that plays a critical role in innate immunity against infectious pathogens through its selective membrane disruptive property. We previously expressed and purified a full-length chicken NK-lysin (cNKL) recombinant protein, and demonstrated its in vitro anti-parasitic activity against the apicomplexan protozoan, Eimeria, the etiologic agent of avian coccidiosis. This study evaluated the in vitro and in vivo anti-parasitic properties of a synthetic peptide (cNK-2) incorporating a predicted membrane-permeating, amphipathic α-helix of the full-length cNKL protein. The cNK-2 peptide exhibited dose- and time-dependent in vitro cytotoxic activity against E. acervulina and E. tenella sporozoites. The cytotoxic activity of 1.5 μM of cNK-2 peptide against E. acervulina following 6h incubation was equal to that of 2.5 μM of melittin, the principal active component of apitoxin (bee venom) that also exhibits anti-microbial activity. Even greater activity was detected against E. tenella, where 0.3 μM of cNK-2 peptide was equivalent to 2.5 μM of melittin. Against Neospora caninum tacyzoites, however, the cytotoxic activity of cNK-2 peptide was inferior to that of melittin. Transmission electron microscopy of peptide-treated E. tenella sporozoites revealed disruption of the outer plasma membrane and loss of intracellular contents. In vivo administration of 1.5 μM of cNK-2 peptide increased protection against experimental E. acervulina infection, as measured by greater body weight gain and reduced fecal oocyst shedding, compared with saline controls. These results suggest that the cNK-2 synthetic peptide is a novel anti-infective peptide that can be used for protection against avian coccidiosis during commercial poultry production.

• Authors: Sung Hyen Lee, Hyun S Lillehoj, Wenbin Tuo, Charles A Murphy, Yeong H Hong, Erik P Lillehoj
• Journal: Veterinary parasitology (Vet Parasitol) Vol. 197 Issue 1-2 Pg. 113-21 (Oct 18 2013) ISSN: 1873-2550 [Electronic] Netherlands
• PMID: 23664157 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Published by Elsevier B.V.

Chemical References

• Coccidiostats
• NK-lysin
• Peptides
• Proteolipids
• Melitten

Topics

• Animals
• Chickens
• Coccidiosis (drug therapy, parasitology, veterinary)
• Coccidiostats (chemistry, pharmacology)
• Dose-Response Relationship, Drug
• Eimeria tenella (drug effects)
• Melitten (pharmacology)
• Peptides (administration & dosage, chemistry, pharmacology)
• Poultry Diseases (drug therapy, parasitology)
• Proteolipids (chemistry)