Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 15, 2006
Publication Date: May 12, 2006
Citation: Hong, Y.H., Lillehoj, H.S., Lee, S., Park, S.S., Lillehoj, E.P. 2006. Cloning and characterization of chicken lipopolysaccharide-induced tnf-a factor. Proceedings of Association of American Immunologists. May 12-16,Boston, MA. p43.
TNF-' is one of the most pleiotropic cytokines in mammals, but has yet to be identified in avian species. In the current study, we isolated a full-length cDNA encoding the chicken homologue of LPS-induced TNF-' factor (LITAF) with an open reading frame of 148 amino acids and a predicted molecular mass of 16.0 kDa. Quantitative RT-PCR analysis showed that chicken LITAF mRNA was predominantly expressed in spleen and intestinal intraepithelial lymphocytes (IELs). LITAF mRNA levels were up-regulated following in vitro stimulation of macrophages for 4 hr with E. coli or Salmonella typhimurium endotoxin, and 18-48 hr after treatment with E. acervulina, E. maxima, or E. tenella. LITAF mRNA was up-regulated more than 700-fold in IELs isolated from E. maxima-infected birds. Recombinant LITAF protein expressed in E. coli or COS7 cells exhibited cytotoxic activity against chicken tumor cell lines in vitro, presumably through autocrine activation of TNF-' or its chicken homologue. This supposition was strengthened by the fact that treatment of chicken macrophages with recombinant LITAF induced the expression of TL1A (TNFSF 15), a member of the TNF ligand super family. We conclude that chicken LITAF may play an important role in the regulation of TNF-' gene expression during the course of coccidiosis. (This project was supported, in part, by the National Research Initiative of the USDA CSREES, grant # 2004-35204-14798).