Human macrophage/monocyte chemotactic protein-4 (MCP-4) is a member of the β chemokine family (C-C) of cytokines. Like eotaxin, MCP-4 is a powerful eosinophil chemoattractant. Additionally, like MCP-3, MCP-4 elicits chemoattraction of monocytes and T lymphocytes. MCP-4 is a peptide of 8.6 kDa that consists of 75 amino acid residues.