CC chemokine receptor type 8, member of the class A family of seven-transmembrane G protein-coupled receptors
CCR8, the receptor for the CC chemokines CCL1 and CC16, is highly expressed on allergen-specific T-helper type 2 cells, and is implicated in the pathogenesis of human asthma. CCL1- and CCR8-expressing CD4+ effector T lymphocytes are shown to have a critical role in lung mucosal inflammatory responses. CCR8 is also a functional receptor for CCL16, a liver-expressed CC chemokine that involved in attracting lymphocytes, dendritic cells, and monocytes. Chemokines are principal regulators for leukocyte trafficking, recruitment, and activation. Chemokine family membership is defined on the basis of sequence homology and on the presence of variations on a conserved cysteine motif, which allows the family to further divide into four subfamilies (CC, CXC, XC, and CX3C). Chemokines interact with seven-transmembrane receptors which are typically coupled to G protein for signaling. Currently, there are ten known receptors for CC chemokines, seven for CXC chemokines, and single receptors for the XC and CX3C chemokines.