MCP-1 belongs to the family of chemotactic cytokines.MCP-1 is expressed by monocytes, vascular endothelial cells, smooth muscle cells, glomerular mesangial cell, osteoblastic cells. MCP-1 has been shown to exhibit biological activities other than Chemotaxis. It can induce the proliferation and activation of killer cells known as CHAK. Elevated levels of MCP-1 are observed in atherosclerotic plaques that are rich in macrophages. The factor activates the tumoricidal activity of monocytes and macrophages in vivo. It regulates the expression of cell surface antigens (CD11c, CD11b) and the expression of cytokines (IL1, IL6). MCP-1 is a potent activator of human basophils, inducing degranulation and the release of histamines. In basophils activated by IL3, IL5 or GM-CSF MCP-1 enhances the synthesis of leukotriene C4.