Cloning, sequencing and regulation of an mRNA encoding porcine interleukin-lβ

Interleukin 1 (IL-1) is a cytokine that mediates a variety of immunological responses. We report here the isolation of a porcine IL-1β cDNA from an alveolar macrophage library. The complete cDNA sequence is 1458 bp in length and has an open reading frame of 803 bp, encoding a 267-amino-acid (aa) protein with an approximate molecular size of 31 kDa. The porcine IL-1β cDNA sequence shows homologies of 82.0, 81.0, 74.0, and 74.0% with the bovine, sheep, human, and murine sequences in the protein coding regions, respectively. Northern blot analysis reveals a single 1.7-kb mRNA species that is differentially regulated by lipopolysaccharide, phorbol myristate acetate, and tumor necrosis factor but is not regulated by human recombinant IL-1. Porcine IL-1β is down-regulated by dexamethasone, polymyxin B, and IL-4 in a fashion kinetically similar to the other reported species.