Chemokine (C motif) ligand 2 (XCL2) is a small cytokine belonging to the XC chemokine family that is highly related to another chemokine called XCL1.It is predominantly expressed in activated T cells, but can also be found at low levels in unstimulated cells. XCL2 induces chemotaxis of cells expressing the chemokine receptor XCR1. 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.