Novel monoclonal antibody recognizing triglyceride-rich oxidized LDLs associated with severe liver disease and small oxidized LDLs in normal subjects.

Background: Triglyceride-rich low-density lipoproteins (TG-rich LDLs) in the plasma of patients with severe liver disease are reported to change macrophages into foam cells in vitro. Methods: Male BALB/c mice were immunized with TG-rich LDLs isolated from the plasma of a patient with severe liver disease. The resulting monoclonal antibody (G11-6) was used in a sandwich enzyme-linked immunosorbent assay (ELISA) in combination with polyclonal anti-apolipoprotein B antibodies. The time course of copper-mediated LDL oxidation was monitored using this ELISA. The results were compared with those of the two commercial ELISAs for oxidized LDLs using DLH or ML25, thiobarbituric acid reactive substances and the optical absorbance for the conjugated dienes generated in lipid peroxides. Furthermore, the lipoprotein fractions separated by gel filtration were tested with this ELISA in healthy volunteers (n = 11) and patients (n = 3) with liver disease. Results: G11-6 reacted with oxidized LDLs during only the early phase of copper oxidation, being distinct from the other monoclonal antibodies and methods. G11-6 was confirmed to react with TG-rich LDLs in patients, while it reacted with small LDL particles in normal controls. Conclusions: The monoclonal antibody G11-6 is useful for detecting oxidized small LDLs in normal controls and oxidized TG-rich LDLs in patients with severe liver disease.