CXCL9 is a small cytokine belonging to the CXC chemokine family that is also known as monokine induced by gamma interferon (MIG). CXCL9 is a chemokine that plays a role in immune responses, it can induce chemotaxis, promote differentiation and proliferation of leukocytes, and cause tissue extravasation. CXCL9 regulates immune cell migration, differentiation and activation by binding to CXCR3 receptor, such as CTLs, NK cells, NKT cells and macrophages. CXCL9 also participates in Th1 polarization and IFN-γ response.