Molecular characterization of an IL-1β gene from ayu, Plecoglossus altivelis

IL-1 beta plays a crucial role as a prototypical proinflammatory cytokine in immune responses and has been shown to affect macrophage functions. However, the effects of putative IL-1 beta homologs on fish macrophages are still less known. Here, we cloned the full-length cDNA sequence of IL-1 beta (aIL-1 beta) gene from ayu, Plecoglossus altivelis. Phylogenetic analysis indicated that aIL-1 beta was closest to that of Atlantic salmon (Salmo salar). Real-time quantitative PCR (RT-qPCR) revealed that aIL-1 beta transcript was mainly expressed in spleen, head kidney and gill, and dramatically increased in various tissues after Listonella anguillarum infection. Subsequently, aIL-1 beta was prokaryotic expressed and purified to prepare anti-aIL-1 beta antibody. After L. anguillarum challenge, the aIL-1 beta mRNA and protein levels were significantly up-regulated in ayu monocytes/macrophages. Moreover, aIL-1 beta neutralization did not change phagocytic capability, but reduced bacterial killing capability in ayu head kidney-derived monocytes/macrophages. Therefore, aIL-1 beta may play an important role in immune response of ayu, especially, contributing to bacterial killing of monocytes/macrophages. (C) 2013 Elsevier Ltd. All rights reserved.