The FOXP3 Luciferase Reporter cell line is a stably transfected Jurkat T cell line which expresses Renilla luciferase reporter gene under the transcriptional control of the Forkhead box P3 (FOXP3) promoter. As a member of the forkhead transcription factor family, FOXP3 is a key transcription factor that functions in the development and function of regulatory T cells. Functional activity of the cell line has been validated by phorbol 12-myristate 13-acetate (PMA) in the presence of ionomycin (Figure 1).