The 2H5 antibody reacts with mouse, human, and rat CCL2 also known as monocyte chemoattractant protein 1 (MCP-1). CCL2 is a 13 kDa chemokine that is produced mainly by monocytes/macrophages but is also expressed by endothelial, fibroblasts, epithelial, smooth muscle, mesangial, astrocytic, and microglial cells. It can be expressed constitutively or after induction by oxidative stress, cytokines, or growth factors. CCL2 regulates the migration and infiltration of monocytes, memory T lymphocytes, and NK cells and is implicated in the pathogeneses of several diseases characterized by monocytic infiltrates, such as multiple sclerosis, psoriasis, rheumatoid arthritis, and atherosclerosis. The 2H5 antibody has been shown to neutralize the biological effects of CCL2 in vivo.