Cardiolipin (CL)

A 1,3-bis(phosphatidyl)glycerol found in many biomembranes with immunologic properties; used in serologic diagnosis of syphilis. When mixed with lecithin and cholesterol cardiolipin will combine with the Wassermann antibody but not with the treponema-immobilizing antibody. SYN: acetone-insoluble antigen, heart antigen.