CXCR3 (Loetscher M et al, 1996) is predominantly expressed on T lymphocytes, and on other lymphocytes (some B cells and NK cells). It is highly induced following cell activation. There are three isoforms, CXCR3-A, CXCR3-B and CXCR3-alt. CXCR3 binds to three highly related ligands in mammals, CXCL9, CXCL10 and CXCL11 (Xanthou G et al, 2003). The ligands then elicit their chemoattractant functions. CXCL9 (CMK; monokine induced by gamma-interferon, MIG; SCYB9) is a T cell chemoattractant (Farber JM, 1993). CXCL10 (IP-10) (Booth V et al, 2002) is secreted by monocytes, endothelial cells and fibroblasts in response to gamma-interferon. It can act as a chemoattractant for monocytes, macrophages, T cells, NK cells and dendritic cells, promote T cell adhesion to endothelial cells and inhibit angiogenesis and bone marrow colony formation. CXCL11 (I-TAC,; iIP-9) (Cole KE et al, 1998) is highly expressed in peripheral blood leukocytes, pancreas and liver. It is regulated by interferon and has potent chemoattractant activity for interleukin-2-activated T cells.