Molecular cloning and characterization of beluga whale (Delphinapterus leucas) interleukin-1 beta and tumor necrosis factor-alpha

Interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) are cytokines produced primarily by monocytes and macrophages with regulato ry effects in inflammation and multiple aspects of the immune response. As yet, no molecular data have been reported for IL-1 beta and TNF-alpha of th e beluga whale. In this study, we cloned and determined the entire cDNA seq uence encoding beluga whale IL-1 beta and TNF-alpha. The genetic relationsh ip of the cytokine sequences was then analyzed with those from several mamm alian species, including the human and the pig. The homology of beluga whal e IL-1 beta nucleic acid and deduced amino acid sequences with those from t hese mammalian species ranged from 74.6 to 86.0% and 62.7 to 77.1%, respect ively, whereas that of TNF-alpha varied from 79.3 to 90.8% and 75.3 to 87.7 %, respectively. Phylogenetic analyses based on deduced amino acid sequence s showed that the beluga whale IL-1 beta and TNF-alpha were most closely re lated to those of the ruminant species (cattle, sheep, and deer). The belug a whale IL-1 beta- and TNF-alpha -encoding sequences were thereafter succes sfully expressed in Escherichia coli as fusion proteins by using procaryoti c expression vectors. The fusion proteins were used to produce beluga whale IL-1 beta- and TNF-alpha -specific rabbit antisera.