ENZYME-LINKED-IMMUNOSORBENT-ASSAY FOR CHOLESTERYL ESTER TRANSFER PROTEIN IN HUMAN SERUM

Cholesteryl ester transfer protein (CETP) plays an important role in the reverse cholesterol transport system. An ELISA for serum CETP protein mass was developed. We have established monoclonal antibodies for CETP and used two different clones to develop the ELISA. Maximum CETP immunoreactivity was obtained in serum samples to which 0.5%, SDS was added. The assay range by this method was from 30 to 2000 ng/ml. The CETP level in sera of normolipemic volunteers determined by this method was 1680 +/- 700 ng/ml (mean +/- S.D, of 101 normolipemic volunteers). Mean intra- and inter-assay coefficients of variation were 6-8 and 9-12%, respectively. CETP mass determined by this ELISA correlated well with cholesteryl ester transfer activity (r = 0.77). We also tested serum samples of patients with CETP gene mutations and found that the CETP mass decreased among the patients with homozygous and heterozygous mutation. This method will help clarify the role of CETP in the metabolism of human HDL and LDL.