C-C motif chemokine 2 (CCL2) is a 76 amino acid Cys-Cys chemokine that has been implicated in the pathogenesis of diseases characterized by monocytic infiltrates, like psoriasis, rheumatoid arthritis and atherosclerosis. It is also known as monocyte chemoattractant protein 1 (MCP1), monocyte chemotactic and activating factor (MCAF), and small inducible cytokine A2. CCL2 is a ligand for the G protein coupled receptors CCR2 and CCR4, and induces chemotactic migration of monocytes, activated T cells, basophils, NK cells and dendritic cells, but not neutrophils or eosinophils. CCL2 can augment monocyte anti-tumor activity and may be involved in the recruitment of monocytes into the arterial wall during the disease process of atherosclerosis. Cytokines are a family of secreted proteins involved in immunoregulatory and inflammatory processes. The CC chemokines are chemotactic cytokines characterized by two adjacent cysteines that induce directed chemotaxis in nearby responsive cells. Recombinant human CCL2 from Molecular Innovations is provided as a native untagged protein. This chemokine is expressed in E. coli then processed, refolded and purified to yield the native, secreted form of the mature chemokine. >98percent pure by SDS-PAGE, HPLC, MALDI-MS and NMR analysis. CCR2 activity verified by intracellular calcium flux using THP1 cells as described by Veldkamp et al, Science Signaling 2008. Add deionized water to desired volume, aliquot and freeze unused portion.