Abstract
The purpose of the present study was to develop and evaluate electroimmunoassay (EIA) for human plasma apolipoprotein (Apo) B and quantify Apo B concentrations in plasma and lipoprotein density fractions from Japanese control healthy subjects, cord blood and pregnant women. LDL of narrow density range (LDL2: 1.030<d<1.050g/ml) was isolated by ultracentrifugation. Antiserum against lipoprotein B was obtained by injecting LDL2 intraperitoneally into rabbits. Double immunodiffusion and immunoelectrophoresis revealed this antiserum is monospecific to lipoprotein B. Electroimmunoassay of Apo B was performed essentially according to the method of Laurell. Concentration of antigen and antibody and time for electrophoresis were investigated. Linear relationship between height of rocket-shaped immunoprecipitates and antigen concentraton from 20 to 160μg/ml was observed utilizing sso-fold dilution of antiserum and electrophoresis for 5 hours with 10 volts/cm. The accuracy of the method was the highest with a peak height of 2 to sem. On the basis of 10 analyses of single sample, the standard error was found to be 2.0%. Apo B concentrations in plasma and lipoprotein density fractions from healthy control subjects, cord blood and pregnant women, were investigated. Apo B concentrations in plasma, VLDL, LDL and HDL from control subjects were 128±40, 11±4,103±7 and 13±sing/100 ml, respectively. Percent distribution of Apo B in VLDL, LDL and HDL were 9.0±3.2, 81.0 ±5.8 and 10.0±3.8%, respectively. Plasma Apo B concentration of the mothers (n=15) was 263±37mg/100ml, which was approximately two times of plasma Apo B concentration of control healthy subjects. However, there was no difference in Apo B distribution in lipoprotein density classes between pregnant women and control. In cord blood (n=15), plas ma Apo B concentration (48±16mg/100ml) was less than one half of control. Percent Apo B distribution in VLDL, LDL and HDL were 8.4, 87.7 and 4.0%, respectively. Percent Apo B concentration in LDL and HDL were higher and lower, respectively, than those in LDL and HDL from control healthy subjects.
