Chemokine （C-C motif） ligand 8 （CCL8） is a small cytokine belonging to the CC chemokine family that was once called monocyte chemotactic protein-2 （MCP-2）. The CCL8 protein is produced as a precursor containing 109 amino acids， which is cleaved to produce mature CCL8 containing 75 amino acids. The gene for CCL8 is encoded by 3 exons and is located within a large cluster of CC chemokines on chromosome 17q11.2 in humans. MCP-2 is chemotactic for and activates a many different immune cells， including mast cells， eosinophils and basophils， （that are implicated in allergic responses）， and monocytes， T cells， and NK cells that are involved in the inflammatory response. CCL8 elicits its effects by binding to several different cell surface receptors called chemokine receptors. These receptors include CCR1， CCR2B and CCR5.
