Submitted to: BARC Poster Day
Publication Type: Proceedings
Publication Acceptance Date: February 1, 1998
Publication Date: N/A
Technical Abstract: Our laboratory is interested in developing novel biotherapeutics to treat chicken coccidiosis and for use as adjuvants. To this end, we have started cloning the most important chicken cytokines, immune proteins that modulate immune responses. A cDNA encoding chicken interleukin-15 (IL-15) was cloned from a CD4+ T cell hybridoma expression library by screening with a rabbit antibody against a protein fraction of conditioned medium containing T cell growth promoting activity. The chicken IL-15 cDNA contains an open reading frame of 143 amino acids with a single potential N-linked glycosylation site. The predicted m.w. of the encoded protein (16 kDa) matched the size of an immunoreactive band on Western blots of E. coli expressing the recombinant IL-15. Amino acid and nucleotide sequence analyses of chicken IL-15 revealed 34% and 46% homology with bovine IL-15 respectively and lesser homologies to other mammalian IL-15s. Analyses of mRNA expression by RT-PCR assays demonstrated that chicken IL-15 gene is expressed in many tissues including spleen, intestine, and muscle, and in established macrophage, T lymphoma and fibroblast cell lines. Activation of spleen cells with Con A enhanced the expression of IL-15 gene transcripts in a time-dependent manner. Mammalian CHO-K1 cells transfected with the chicken IL-15 cDNA secreted a biologically active protein supporting the growth of Con A activated spleen lymphocytes. Continuous culture of spleen Con A lymphoblasts with chicken IL-15 over two months resulted in an enriched T lymphocyte population expressing the gdTCR, CD8, and CD3 cell surface antigens. This new reagent can now be tested for its effects on chicken disease responses.