The effect of intraperitoneally administered recombinant IL-1beta on immune parameters and resistance to Aeromonas salmonicida in the rainbow trout (Oncorhynchus mykiss).

The present work provides the first information concerning the immunostimulatory activity of trout recombinant interleukin-1 beta (rIL-1β) in vivo. The predicted rainbow trout mature IL-1β peptide was produced as a recombinant protein in Escherichia coli. Optimal migration of peritoneal leucocytes and rIL-1β induced phagocytosis occurred following intraperitoneal injection of 1 μg of the recombinant protein. Moreover, systemic IL-1β, COX-2 and lysozyme II gene expression was enhanced following ≥1 μg rIL-1β administration. Finally, resistance to Aeromonas salmonicida, the causative agent of furunculosis, was augmented at early times (2 days) post-injection of 1 μg rIL-1β.