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Title: Characterization of novel lytic peptide secreted by intestinal intraepithelial lymphocytes infected with coccidia

Author
item Lillehoj, Hyun
item Lee, Sung Eun
item Jenkins, Mark

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/11/2007
Publication Date: 7/14/2007
Citation: Lillehoj, H.S., Lee, S.H, Jenkins, M.C., Hong, Y.H. 2007. Characterization of novel lytic peptide secreted by intestinal intraepithelial lymphocytes infected with coccidia. Proceedings of American Avian Veterinary Pathologists meeting. July 14-18. Washington, D.C.

Interpretive Summary: With increasing concerns over the use of drugs in animal production and wide spread incidence of drug resistant coccidia strains associated with commonly used drugs, discovery of novel compound which has anti-microbial activity against wide variety of pathogens will be important. In this paper, ARS scientists describe novel anti-microbial peptide which are secreted by bird's lymphocytes during coccidiosis. This novel peptides called NK-lysin is produced by lymphocytes of poultry and its production is highly enhanced during parasitic infection indicating protective role of NK lysin in infections. The full-length gene encoding NK lysin was cloned and recombinant NK lysin protein was produced. Recombinant NK lysin protein kills chicken tumor cells and demonstrates lytic activity against coccidia parasites. In conclusion, gene encoding chicken NK-lysin has been cloned and its product show great potential as novel immunotherapeutic agent against coccidia parasites. This information will help industry to devise novel method to control coccidia parasites.

Technical Abstract: The inflammatory response to parasites is mediated by multiple host factors. In this report, we present molecular and functional characterizations of a novel immune mediator whose gene expression increased following infection with Eimeria. NK-lysin is an anti-microbial and anti-tumor protein expressed by NK cells and T lymphocytes. Full-length clone encoding chicken NK-lysin was isolated from intestinal intraepithelial lymphocytes (IELs) cDNA library. NK-lysin is consisted of an 868 bp DNA sequence with an open reading frame of 140 amino acids and a predicted molecular mass of 15.2 kDa. Comparison of its deduced amino acid sequence showed less than 20% identity to mammalian NK-lysins. The tissue distribution of NK-lysin mRNA revealed highest levels in intestinal IELs, intermediate levels in splenic, peripheral blood lymphocytes and lowest levels in thymic, bursa lymphocytes. The kinetics of NK-lysin mRNA expression indicated that, whereas infection with E. acervulina induced maximum expression only at 7-8 days post-infection, E. maxima and E. tenella elicited biphasic responses at 3-4 and 7-8 days post-infection. Finally, recombinant chicken NK-lysin expressed in COS7 cells exhibited anti-tumor cell activity against LSCC-RP9. We conclude that chicken NK-lysin plays important roles during anti-microbial and anti-tumor defenses.