The components of apo A-I and B-100 particles isolated from human plasma by immuno-affinity columns with monoclonal antibodies were analyzed and characterized by using the procedures already described. The apoprotein compositions of apo A-I particles were apo A-I 77%, apo A-II 20%, apo C-II 1%, apo C-III 1%, and apo E 1%. The lipid compositions of apo A-I particles were phospholipid 54%, cholesterol ester 27%, free cholesterol 11%, triglyceride 8%. The component of apo A-I was quite similar to that of HDL. The apoprotein compositions of apo B-100 particles were apo B-100 98% and the mixture of apo C-II and apo C-III 2%. The lipid compositions of apo B-100 were phospholipid 26%, cholesterol ester 28%, free cholesterol 17%, and triglyceride 29%. The component of apo B-100 particles was almost identical to those of VLDL and LDL fractions. It is possible to measure using these affinity columns the amonts of cholesterol and proteins in apo A-I and apo B-100 particles.
