Background：Human CXCR3, also known as GPR9, is a chemokine receptor that binds CXCL9, CXCL10, and CXCL11. It is a 38 kD seven-pass transmembrane receptor coupled to G-protein. CXCR3 is highly expressed by T cells （Th1）, natural killer cells （NK cells）, dendritic cells, mast cells, alveolar macrophages, eosinophils, and human airway epithelial cells. CXCR3 is important for effector lymphocyte recruitment into inflamed tissue in various inflammatory and autoimmune diseases, such as chronically inflamed liver, Crohn's disease, rheumatoid arthritis, multiple sclerosis, and inflammatory skin diseases.
