The Comparisons between Apolipoprotein A, A-I and A-II Quantitative Plates by the Method of SRID

Abstract

The concentrations of serum apolipoprotein A (M-Partigen-Apolipoprotein A, Behringwerke), A-I and A-II (Daiichi pure) were determined in 27 normal and hyperlipidemic subjects by the commercially developed SRID method. Apo A concentration was higher than sum of apo A-I and A-II concentrations, and the apo A/apo A-I+A-II ratio was 1.29±0.02. Apo A correlated with apo A-I+A-II (r=0.98). The same results were obtained even though specially prepared standard serum for each methods were determined by the different method. These data suggested that the differences between apo A and apo A-I+A-II concentrations which observed in the human serum were induced by the differences of indicated values of standard serum in each method.
Whole serum formed single precipitin arc with a migration similar to HDL on crossed immunoelectrophoresis with anti apo A (anti human α-lipoprotein) serum. Delipidated HDL formed precipitin arcs of apo A-I and A-II with mixture of anti apo A-I and anti apo A-II serum. Delipidated HDL formed single precipitin arc with anti apo A serum on immunoelectrophoresis, but not formed on rocket immunoelectrophoresis and Ouchterlony method. Delipidated HDL formed clear precipitin rings on apo A-I and apo A-II SRID plates, but formed unclear rings on apo A plate. These difference of the reactions between anti apo A serum and delipidated HDL seems to suggest that immunoreactivity of HDL was not identical with that of apo A-I or apo A-II.