Cholesterol determination in serum after fractionation of lipoproteins by immunoprecipitation.
We investigated the immunoprecipitation of apolipoprotein B-binding lipoproteins, or of apo A-I- and apo C-binding lipoproteins, by delipidated antiserum for measuring cholesterol in the nonprecipitated lipoprotein fractions. After immunoprecipitation of serum with delipidated anti-apo B, we determined by immunoelectrophoresis that no beta- or pre-beta lipoproteins were present, whereas alpha-lipoproteins remained in the supernate. Conversely, after immunoprecipitation with an antiserum against apo A-I + apo C, only lipoproteins with beta-mobility were detected and no apo B from beta-lipoproteins was in the precipitate. The concentration of cholesterol in the supernate after immunoprecipitation with anti-apo B correlated highly (r = 0.93, n = 118) with cholesterol measured after precipitation with phosphotungstic acid/MgCl2. The cholesterol concentration after immunoprecipitation with anti-apo AI and anti-apo C correlated similarly well (r = 0.94, n = 145) with the LDL-cholesterol calculated by Friedewald's formula in serum specimens reflecting moderate hyperlipoproteinemia.
D001053:Apolipoproteins / Q000097:blood; D002352:Carrier Proteins / Q000097:blood; D011232:Chemical Precipitation; D002784:Cholesterol / Q000097:blood*; D008076:Cholesterol, HDL / Q000097:blood; D006801:Humans; D007120:Immunochemistry; D007122:Immunoelectrophoresis; D008074:Lipoproteins / Q000097:blood*
D001053:Apolipoproteins; D002352:Carrier Proteins; D008076:Cholesterol, HDL; D008074:Lipoproteins; D002784:Cholesterol