CCR8 is a GPCR that binds primarily to the chemokine I-309 (CCL1) (Roos et al., 1997). CCR8 is expressed primarily on Th2 cells although its functional role in T cell recruitment to sites of allergic inflammation is controversial (Chensue et al., 2001; Goya et al., 2003). CCR8+ T-cells are abundant in skin, and rare or absent in the GI tract and peripheral blood, indicating a role in skin-homing of T-cells (Schaerli et al., 2004). In addition, monocyte-derived dendritic cells express CCR8 and utilize CCR8 during mobilization from skin to the lymph node (Qu et al., 2004). The cloned human CCR8-expressing cell line is made in the Chem-1 host, which supports high levels of recombinant CCR8 expression on the cell surface and contains high levels of the promiscuous G protein Gα15 to couple the receptor to the calcium signaling pathway. Thus, the cell line is an ideal tool for screening for agonists, antagonists and modulators at CCR8.