Interferon regulatory factor 8 (IRF8, interferon consensus sequence-binding protein, ICSBP) is a transcription factor of the interferon (IFN) regulatory factor (IRF) family. Proteins of this family are composed of a conserved DNA-binding domain in the N-terminal region and a divergent C-terminal region that serves as the regulatory domain. The IRF family proteins bind to the IFN-stimulated response element (ISRE) and regulate expression of genes stimulated by type I IFNs, namely IFN-. and IFN-.. IRF family proteins also control expression of IFN-. and IFN-.-regulated genes that are induced by viral infection.