Rat MCP-1 (monocyte chemoattracctant protein-1) is a 148-amino acid CC chemokine with a NH2-terminal sequence of 29 residues as a signal sequence. This rat MCP-1/JE is 49-amino acid longer than human MCP-1 at 3’-end. This 3’-end is a serine and threonine rich zone, which is probably responsible for the extensive O-glycosylation. MCP-1 is produced by a wide range of cell types as a reaction to diverse inflammatory stimuli and is a chemotactic factor that attracts monocytes and basophils but not neutrophils or eosinophils. MCP-1 augments monocyte anti-tumor activity and has been implicated in the pathogenesis of diseases characterized by monocytic infiltrates, like psoriasis, rheumatoid arthritis or atherosclerosis. In atherosclerosis MCP-1 may has been implicated to be involved in the recruitment of monocytes into the arterial wall during the disease process.