MCP-1was characterized as a monocyte-specific chemoattractant that was later shown to attract also T lymphocytes and NK cells.
MCP-1 is mainly expressed by macrophages in response to a wide range of cytokines such as IL-6, TNF-alpha and IL-1beta, but can, upon stimulation, also be produced by a variety of cells and tissues, such as fibroblasts, endothelial cells or certain tumor cells.
Because of its target cell specificity, MCP-1 was postulated to play a pathogenic role in a variety of diseases characterized by mononuclear cell infiltration, including atherosclerosis, rheumatoid arthritis and allergic responses. In basophils, MCP-1 is highly effective as a stimulus of histamine release but has only weak chemotactic activity. Additionally it has been shown to chemoattract CD4+ and CD8+ T lymphocytes.