Molecular characterization of duck interleukin-17

Interleukin-17 (IL17), belonging to the Th17 family, is a proinflammatory cytokine produced by activated T cells. A 1034 bp cDNA encoding duck IL17 (duIL17) was cloned from Con A-activated splenic lymphocytes of ducks. The encoded protein, which is predicted to consist of 169 amino acids, has a molecular weight of 18.8 kDa and includes a 29 residue NH₂-terminal signal peptide, a single potential N-linked glycosylation site, and six cysteine residues that are conserved in mammalian IL17. The duIL17 shared 84% amino acid sequence identity with the previously described chicken IL17 (chIL17), 36-47% to mammalian homologues, and open reading frame 13 of Herpesvirus saimiri (HVS13). The genomic structure of duIL17 was quite similar to its chicken and mammalian counterparts. The duIL17 mRNA expression was detected only in Con A-activated splenic lymphocytes by RT-PCR, although its expression was undetectable in a variety of normal tissues. Two mAbs against chIL17 showed cross-reactivity with duIL17 as detected by indirect ELISA and Western blot analysis. These findings indicate that the structure of IL17 is highly conserved among poultry, and two mAbs detecting common epitopes of IL17 are available for molecular and immunological studies of IL17 in birds.