Immunohistochemical localization of apolipoprotein B in human atherosclerotic lesions.

A peroxidase-antiperoxidase immunohistochemical method was used to detect the presence of intracellular and extracellular apolipoprotein B (apo B) in paraffin sections of human abdominal aortas and coronary arteries with and without atherosclerotic involvement. The four aortas studied disclosed both intracellular and extracellular apo B in areas in which lipid was found by oil red O staining. Coronary arteries also demonstrated abundant extracellular apo B but failed to disclose intracellular apo B in cells with stainable lipid. Immunohistochemical detection of intracellular apo B in raised aortic lesions but not in cells of coronary lesions suggests that arteries that contain detectable amounts of intracellular apo B correspond to arteries that usually have earlier atherosclerotic involvement.