Description
Chemokine (C-X-C motif) ligand 9 (CXCL9), also known as monokine induced by interferon gamma (MIG), is a small cytokine belonging to the CXC chemokine family. The CXCL9 gene is induced in macrophages and in primary glial cells of the central nervous system specifically in response to IFNγ. CXCL9 has been shown to be a chemoattractant for activated T-lymphocytes and TIL but not for neutrophils or monocytes. The human CXCL9 cDNA encodes a 125 amino acid residue precursor protein with a 22 amino acid residue signal peptide that is cleaved to yield a 103 amino acid residue mature protein. CXCL9 has an extended carboxy-terminus containing greater than 50% basic amino acid residues and is larger than most other chemokines. A chemokine receptor (CXCR3) specific for CXCL9 and IP-10 has recently been cloned and shown to be highly expressed in IL-2-activated T-lymphocytes.