Cloning and functional characterization of chicken interleukin-17D

The chicken interleukin-17D was cloned from a testis cDNA library prepared from the Korean native chicken. The full-length chicken IL-17D (chIL-17D) cDNA consisted of a 348 nucleotide sequence encoding an open reading frame of 116 amino acids with a predicted molecular mass of 13.3 kDa. Comparison of the deduced amino acid sequence of chIL-17D with hornologous proteins from human, mouse and opossum revealed 64%, 53% and 76% identity, respectively, including six conserved cysteine residues present in the mammalian polypeptides. The chlL-17D gene transcript was expressed in a wide range of tissues, and highest levels were in pancreas, thymus and lung. Following Eimeria maxima infection, levels of the chlL-17D mRNA were Up-regulated in the intestinal jejunum, bursa, lung, and spleen but decreased in the thymus. Infected chickens also expressed greater levels of chlL-17D mRNA in CD4(+), CD8(+) and TCRI+ intestinal intraepithelial lymphocytes while decreased expression was seen in TCR2(+) cells. Treatment of CHCC-OU2 fibroblasts with chlL-17D recombinant protein induced the expression of IL-6 and IL-8. Collectively, these results Suggest that chL-17D has structural and functional similarities to mammalian IL-17Ds and that it plays an important role in local gut innate immune responses during experimental coccidiosis. Published by Elsevier B.V.