Characterization of a specific monoclonal antibody 9F5-3a and the development of assay system for oxidized HDL

We obtained a monoclonal antibody 9F5-3a against oxidative low-density lipoprotein (LDL) modified with CuSO4 and established a sandwich ELISA for detection of oxidized high-density lipoprotein (oxHDL). The 9F5-3a was reacted strongly with oxHDL and to a lesser degree with oxLDL and LDL. In contrast, little or no reactivity was found with HDL. When the generation of oxHDL was limited by the addition of alpha-tocopherol and catalase, reactivity to 9F5-3a was reduced. Incubation of oxHDL with excess lyso-phosphatidylcholine (lyso-PC) also reduced immunoreactivity, but not by only lyso-PC. These results suggested that the epitope is possibly associated with oxHDL-linked lyso-PC induced mainly by the hydroxyl radical.