IMMUNOSTAINING OF HUMAN AUTOPSY AORTAS WITH ANTIBODIES TO MODIFIED APOLIPOPROTEIN-B AND APOPROTEIN(A)

A systematic immunohistochemical study of different stages of atherosc lerosis in human aortas was performed using several antibodies. Becaus e oxidation of lipoproteins could be a key event in atherogenesis, an antibody against apolipoprotein B (apoB) from low-density lipoprotein (LDL) modified with the lipid peroxidation-specific aldehyde, 4-hydrox ynonenal (4-HNE) (anti-4-HNE-apoB), was raised in rabbits. This antibo dy recognizing 4-HNE protein adducts was used in concert with an antib ody to apo(a) from lipoprotein(a), considered also potentially atherog enic, as well as with an antibody and a monoclonal antibody (mAb) to a poB. Autopsy material from 12 corpses was investigated. The immunohist ochemical investigation by the alkaline-phosphatase technique included control specimens regarding postmortem artifacts by autolysis and oxi dation. The results from six specimens from five corpses are presented . A positive staining with the antibody to apoB but not with anti-4-HN E-apoB was seen in the normal intima. The thickened intima of early, t ransitional, and advanced atherosclerotic lesions and atheromata showe d a predominantly extracellular staining with all antibodies and the a pplied mAb. To test the specificity of the staining, antibodies preads orbed by the appropriate antigens and nonimmune sera were used, giving negative results. These findings indicated a colocalization of epitop es derived from lipid peroxidation of polyunsaturated fatty acids and epitopes specific for apoB and apo(a) during atherogenesis in humans.