Improvement of electroimmunoassay for apolipoproteins B and A-I

A reliable method for determining serum apoprotein levels is an essential condition for investigating the role of apoproteins in atherogenesis. Electroimmunoassay according to Laurell has been studied and applied with some modifications for the determination of the two main apoproteins: Apo A-I and Apo B. Apo B immunoplates containing 0.4% v/v of rabbit anti-Apo B antiserum were processed for 4 h at 10 V/cm. Samples were incubated at 52 degrees C for 3 h, diluted and then 10 microliter were seeded in each well. Apo A-I immunoplates (8% v/v of sheep antiserum) were processed for 24 h at 2 V/cm. Agarose gel concentration, exsiccation procedure and staining were the same for both apoproteins. The method was standardized employing a secondary standard consisting of a serum pool obtained from normal subjects. Apo A-I and Apo B levels of the pool have been previously determined employing as primary standards the HDL3 (1.120-1.230 g/ml) and the LP-B (1.035-1.050 g/ml) fractions, respectively, which were isolated by preparative ultracentrifugation. Preliminary observations from a study on 20 healthy volunteers with normal lipid levels revealed different apoprotein levels in young men and women and significant differences between postmenopausal women and women in the fertile age