Purity >95% as determined by SDS-PAGE. Monocyte chemotactic protein 2 (MCP-2), also known as CCL8, is a cytokine that is important during allergic and inflammatory responses. MCP-2 activates mast cells, eosinophils, and basophils through the G protein-coupled chemokine receptors CCR1, CCR2B, and CCR5. MCP-2 signaling through the CCR5 receptor also functions as a natural inhibitor of the human immunodeficiency virus, type 1 (HIV-1).