COMPARISON OF MONOCLONAL AND POLYCLONAL ENZYME-LINKED IMMUNOABSORBENT(ELISA) ASSAYS FOR SERUM LP(A) AND DIFFERENCES IN REACTIVITIES TO LP(A) PHENOTYPES

We have prepared a monoclonal antibody to Lipoprotein(a)[Lp(a)] and ha ve used it to develop an ELISA test for assaying Lp(a) in serum. The m onoclonal antibody employed in the assay system reacts uniformly with S1,S2,S3 and B phenotypes of isoforms, and no cross-reaction with plas minogen at a concentration of 100 mg/dL was observed. Results of the m onoclonal ELISA assay were similar to those obtained with a polyclonal antibody ELISA method and demonstrated a correlation coefficient, r=0 .99 with the equation for the regression line:Y(proposed)= 1.06 X(poly clonal antibody reference ELISA test) = 0.36(N = 51). Inter- and intra -assay precision(CVs) of the monoclonal ELISA assay were between 2.2-3 .6% at a mean Lp(a) concentration range of 19.1-68.2 mg/dL,(N = 12). A ssay results of various standards were compared by both monoclonal and polyclonal antibody ELISA tests. We observed some discrepancies betwe en expected concentrations and the polyclonal antibody ELISA assay res ults, which is thought to be more uniformly reactive to the various Lp (a) phenotypes. The monoclonal antibody employed in our proposed metho d reacts uniformly with Lp(a) phenotypes, and the assay exhibits excel lent sensitivity, specificity, and accuracy and is well suited for cli nical use. (C) 1995 Wiley-Liss, Inc.