MCP-2 and MCP-3 are two monocyte chemotactic proteins produced by human MG-63 osteosarcoma cells. Both MCP-2 and MCP-3 are members of the C-C family of chemokines and share 62% and 71% amino acid sequence identity, respectively, with MCP-1. MCP-3 also shares 58% amino acid identity with MCP-2.