C-X-C motif chemokine ligand 9 (CXCL9) (CXCL9)

C-X-C motif chemokine ligand 9 (CXCL9), also known as Monokine induced by gamma interferon (MIG), is a member of the CXC chemokine family primarily induced by interferon-gamma (IFN-γ) (UniProt P40189). It acts as a potent chemoattractant for activated T lymphocytes and natural killer (NK) cells through its interaction with the CXCR3 receptor (Frontiers in Oncology, 2021). In clinical oncology, CXCL9 is a critical component of the 'T-cell-inflamed' tumor microenvironment and serves as a significant biomarker for predicting patient response to immune checkpoint inhibitors such as anti-PD-1 therapy (Cancer Cell, 2019). Beyond its role in anti-tumor immunity, dysregulated or excessive CXCL9 expression is implicated in the pathogenesis of various autoimmune diseases, including systemic lupus erythematosus and rheumatoid arthritis, as well as in transplant rejection and graft-versus-host disease (PubMed Central, 2021). Therapeutic strategies currently under investigation include the use of dipeptidyl peptidase-4 (DPP-4) inhibitors to prevent the enzymatic inactivation of CXCL9, and experimental fusion proteins designed to enhance immune cell recruitment to tumors (PNAS, 2025).

Other names

Monokine induced by gamma interferonMIGGamma-interferon-induced monokineSmall inducible cytokine B9SCYB9HumigChemokine (C-X-C motif) ligand 9

Promotion of T-cell and NK-cell recruitment via CXCR3 agonism (as a CXCL9-Fc fusion protein); prevention of N-terminal cleavage and inactivation of CXCL9 through the inhibition of dipeptidyl peptidase-4 (DPP-4); and neutralization of pro-inflammatory activity using experimental monoclonal antibodies (preclinical).