An NF-κB luciferase reporter construct is stably integrated into the genome of CHO-K1 cells. The firefly luciferase gene is controlled by the NF-κB response element located upstream of the TATA promoter. Following activation by stimulants, endogenous NF-κB transcription factors bind to the DNA response elements to induce transcription of the luciferase gene._x000D_The NF-κB-luciferase / CHO-K1 cell line is suitable for monitoring the activity of NF-κB transcription factor through luminescence readout.). This cell line responds to human cytokine IL-1β, responds moderately to human TNF, and does not respond to human IFN-λ (2 µg/ml). Reducing the amount of serum during incubation period may increase the sensitivity to cytokines. Since CHO-K1 cells do not express endogenous human proteins, this cell line provides an excellent platform to enable exogenous expression of a protein of interest to study its downstream effect on NF-κB signaling.