Clone REA516 recognizes the human and mouse interferon regulatory factor 8 (IRF-8) antigen, a 50 kDa transcription factor, which is also known as interferon consensus sequence–binding protein (ICSBP). IRF-8 belongs to the family of interferon regulatory transcription factors, which consists of nine members in both human and mice and is characterized by a conserved N-terminal DNA-binding domain with a unique tryptophan pentad repeat. IRF-8 is expressed at very high levels in mononuclear phagocytes, and regulates granulocyte/macrophage differentiation and dendritic cell (DC) development. Acting in heterodimeric complexes with other transcription factors, IRF-8 also controls the transcriptional response of mature myeloid cells to interferons and Toll-like receptor agonists, a response in which IRF-8 binds and transactivates the promotors of IL12B and NOS2. IRF-8 knockout mice display a loss of CD8a

lymphoid DCs, CD103

tissue myeloid DCs, and plasmacytoid DCs.