HDL biology
A new immunoassay measuring CETP activity via radiolabeled cholesteryl ester transfer matches the ultracentrifugation method with r=0.94, without separating donor and acceptor lipoproteins (Clin Chem 1995)
Original title: Immunospecific scintillation proximity assay of cholesteryl ester transfer protein activity
A novel immunospecific scintillation proximity assay was developed to measure CETP activity in total human serum and reconstituted mixtures, based on transfer of radiolabeled cholesteryl esters from a tracer dose of labeled HDL3 to unlabeled apo B-containing lipoproteins. The radioactivity in the apo B-containing fraction is measured without physically separating donor and acceptor lipoproteins, using ternary complexes formed with radiolabeled apo B-containing lipoproteins, anti-apo B antibodies from sheep, and anti-sheep antibody-labeled fluoromicrospheres. CETP activity values obtained with this assay corresponded well with the ultracentrifugation method (n = 70, r = 0.94, P = 0.0001), and values for fresh versus frozen serum also corresponded well (n = 70, r = 0.93, P = 0.0001).
Original abstract
We describe a novel, immunospecific scintillation proximity assay for determining cholesteryl ester transfer protein (CETP) activity in total human serum and in reconstituted experimental mixtures. The assay is based on the measurement of radiolabeled cholesteryl esters transferred from a tracer dose of biosynthetically labeled high-density lipoprotein subfraction 3 to unlabeled apolipoprotein (apo) B-containing lipoproteins. The radioactivity content of the apo B-containing lipoprotein fraction can be evaluated without separating the donor from the acceptor lipoprotein substrates, and is measured through the formation of ternary complexes involving the radiolabeled apo B-containing lipoproteins, specific anti-apo B antibodies from sheep, and anti-sheep antibody-labeled fluoromicrospheres. Good correspondences were observed between CETP activity values obtained either with the ultracentrifugation method or the immunospecific scintillation proximity assay (n = 70; r = 0.94; P = 0.0001), and between values obtained for either fresh or frozen serum samples (n = 70; r = 0.93; P = 0.0001). Because of its potential for automation, the immunospecific scintillation proximity assay may constitute a convenient tool to measure serum CETP activity in the clinical laboratory.
Summary written by cetpinhibition.org from the published abstract; figures as published. Page updated 19 August 2026. Methods.