Human macrophage/monocyte chemotactic protein-3 (MCP-3) is a 8.5kD protein containing 76 amino acids residues. It plays an important role in the inflammatory response of blood monocytes, tissue macrophages, and eosinophils. The gene encoding this protein encodes monocyte chemotactic protein 3, a secreted chemokine which attracts macrophages during inflammation and metastasis. It is a member of the C-C subfamily of chemokines which are characterized by having two adjacent cysteine residues. The protein is an in vivo substrate of matrix metalloproteinase 2, an enzyme which degrades components of the extracellular matrix. This gene is part of a cluster of C-C chemokine family members on chromosome 17q.