Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/10/1998
Publication Date: N/A
Technical Abstract: Interleukin-18 (IL-18) is a pleiotrophic cytokine produced by Kupffer cells, keratinocytes, and activated macrophages. The pro-inflammatory effects of IL-18 include induction of interferon-g production, Fas ligand expression, and activation of nuclear factor kB. Reverse transcription- polymerase chain reaction (RT-PCR) was used to amplify a fragment of bovine eIL-18 using mRNA prepared from mononuclear cells isolated from peripheral blood. PCR primers were selected from conserved regions of human, mouse, rat, and porcine IL-18; and a 248 bp fragment was amplified and sequenced that had 92% homology to the coding region of porcine IL-18. The sequence of this 248 bp fragment was confirmed by RT-PCR of RNA isolated from the adrenal gland, kidney, and liver. New PCR primers were designed based upon the bovine fragment sequence and used to amplify a 723 bp cDNA of bovine IL-18, which included the entire coding region. The bovine cDNA codes for a 178 amino acid polypeptide, which shares 89%, 77%, and 65% identity with that of porcine, human, and murine IL-18, respectively. Bovine IL-18 was expressed in Escherichia coli using a pMAL -c2 protein fusion and expression system. The predicted amino acid sequence of bovine IL-18 has a mass of 19.8 kDa and a pI of 5.05.