Interleukin-6 (IL-6) is a multifunctional cytokine,playing important roles in immune defense. To better understand the transcriptional principle and immune mechanism of fish il-6,five reporter plasmids of the Megalobrama amblycephala il-6 promoter were constructed,co-transfected with the internal control plasmid pRL-TK into carp EPC cell,induced by LPS,and the luciferase activity was then detected after 24 h.The results showed that compared with the negative control PGL3-basic group,the luciferase activity of the PGL3-IL-6P-0,PGL3-IL-6P-1,PGL3-IL-6P-2,PGL3-IL-6P-3 and PGL3-IL-6P-4 groups were increased,and the PGL3-IL-6P-4 group showed the highest luciferase level,suggesting that the promoter deletion (-379 to +34) contains the core promoter region of the il-6 promoter.After stimulation by 100 ng/mL LPS,the luciferase activity of the PGL3-IL-6P-4 group was significantly activated,while that of the other groups did not change significantly,further indicating that PGL3-IL-6P-4 indeed contains the core promoter region and the potential transcription factor NF-κB and C/EBPβ in this promoter region may play primary roles in response to LPS induction.