CCR4 is a chemokine receptor and is preferentially expressed on type 2 helper T (Th2-type) cells. In contrast to other chemokine receptors, the expression of CCR4 and CCR8 on Th2 cells is transiently increased following TCR and CD28 engagement. Moreover, activated Th1 cells up-regulate CCR4 expression and functional responsiveness to thymus- and activation-regulated chemokine. Chemokines are a group of small (approximately 8 to 14 kD), mostly basic, structurally related molecules that regulate cell trafficking of various types of leukocytes through interactions with a subset of 7-transmembrane, G protein-coupled receptors. Chemokines also play fundamental roles in the development, homeostasis, and function of the immune system, and they have effects on cells of the central nervous system as well as on endothelial cells involved in angiogenesis or angiostasis. Chemokines are divided into 2 major subfamilies, CXC and CC, based on the arrangement of the first 2 of the 4 conserved cysteine residues; the 2 cysteines are separated by a single amino acid in CXC chemokines and are adjacent in CC chemokines.
C-C chemokine receptor type 4; C-C CKR-4; CCR-4; CD194; chemokine (C-C motif) receptor 4; chemokine (C-C) receptor 4; K5-5; MGC88293