Cloning and characterization of bovine interleukin-32 beta isoform

Interleukin-32 (IL-32) is a new cytokine produced mainly by T-cells, natural killer cells, and epithelial cells after stimulation with IL-2, IL-12 plus IL-18, and IFNγ, respectively. IL-32 induces various proinflammatory cytokines such as TNFα, IL-1β, IL-6, and IL-8 in monocytes and macrophages. In this study, we cloned bovine IL-32 cDNA from peripheral blood mononuclear cells (PBMC) of a Holstein (Bos Taurus). The bovine IL-32 cDNA has an entire open reading frame, encoding 171 amino acid residues and the deduced amino acid sequence has 27.5% identity with human IL-32 beta isoform. Recombinant bovine IL-32 protein was produced in E. coli and its molecular weight was approximately 26 kDa. The biological activity of the bovine IL-32 was examined for cytokine induction using human monocytic THP-1 cells and bovine PBMC. The THP-1 cells responded to stimulation by recombinant bovine IL-32 and produced IL-8. Stimulation by recombinant bovine IL-32 induced mRNA for TNFα and IL-6 in bovine PBMC suggesting conservation of the biological activity and function in cattle.