CXCR3 is a 7-TM GPCR that is selective for the CXC chemokines IP10, I-TAC and MIG (Loetscher et al., 1996). Binding of IP10 and MIG to CXCR3 induces Ca2+ mobilization, chemotaxis and inflammatory responses of T lymphocytes, and also act as potent inhibitors of angiogenesis. CXCR3 is highly expressed in IL-2-activated T lymphocytes in vitro (Loetscher et al., 1996), and in T lymphocytes present in inflamed tissues in rheumatoid arthritis and multiple sclerosis (Balashoy et al., 1999; Qin et al., 1998). In vivo, neutralization of CXCR3 inhibits experimentally induced type I diabetes (Frigerio et al., 2002), peritonitis (Xie et al., 2003), and post-lung transplantation bronchiolitis obliterans syndrome (Belperio et al., 2002). Cloned human CXCR3 receptor-expressing ChemiBrite cells were made by stable transfection of HEK293 cells with ChemiBrite clytin, the receptor and a promiscuous G protein to couple the receptor to the calcium signaling pathway. These stability-tested cells are ready for luminescent analysis of agonists, antagonists and modulators at the CXCR3 receptor.