mouse monoclonal IgG2a; CD46 Antibody (E4.3) is an IgG2a κ mouse monoclonal CD46 antibody (also designated CD46 antibody or Membrane Cofactor Protein (MCP) antibody) that detects CD46 of human origin by WB, IP, IF and FCM. CD46 Antibody (E4.3) is available as the non-conjugated anti-CD46 antibody form, as well as multiple conjugated forms of anti-CD46 antibody, including agarose, HRP, PE, FITC and multiple Alexa Fluor® conjugates. CD46, also called membrane cofactor protein (MCP), is a transmembrane glycoprotein that exists as a non-disulfide-linked dimer. CD46 regulates the complement cascade by inhibiting C3b and C4b deposited on self tissue. CD46 is a cofactor that binds to C3b and C4b, allowing their degradation by a plasma serine protease called factor I. This function resides in the complement control protein repeats (CCPs), with CCP1-4 essential for regulation. CD46 is widely distributed on thymocytes, T cells, B cells, monocytes, granulocytes, NK cells, platelets, endothelial cells, epithelial cells, fibroblasts, placenta and sperm, but not on erythrocytes. It is the major high affinity receptor for measles virus and human herpes virus. Mouse cells ubiquitously express CRRY, which is a functional ortholog of human decay-accelerating factor (DAF; CD55) and membrane cofactor protein (MCP; CD46).