The immune responses of common carp, Cyprinus carpio L., injected with carp interleukin-1β gene

The function of the common carp, Cyprinus carpio L., interleukin-1β (IL-1β) gene was studied by DNA injection. To investigate the immune responses to IL-1β, a plasmid construct of cytomegalovirus (CMV)-driven carp IL-1β was injected into the epaxial muscle of carp. IL-1β protein expressed in serum on 1, 3, and 5 days after plasmid injection was quantified by ELISA and immunohistochemistry. IL1-β gene injection increased proliferation of the lymphocytes by phytohemagglutinin (PHA). Macrophage functions, such as production of superoxide anion and phagocytosis, also were stimulated by IL-1β gene injection. Moreover, an increase in resistance to Aeromonas hydrophila infection was recorded in IL-1β-injected fish compared with control fish. Thus, the cloned homolog of IL-1β from carp has all the functional similarities to the mammalian IL-1β gene.