CHARACTERIZATION OF A MONOCLONAL-ANTIBODY (HB-22) AND DEVELOPMENT OF AN ELISA FOR HUMAN APOLIPOPROTEIN-A-I

We describe the production and characterization of a high-affinity mon oclonal antibody, HB-22, for apolipoprotein (ape) A-I, a major protein of human high-density lipoproteins (HDL). Including Tween 20 in the r eaction mixture increased the binding capacity of HB-22 to apo A-I. HB -22 showed monospecific reactivity with HDL or apo A-I, displaying no cross-reactivity with apo A-II, intermediate-, low-, or very-low-densi ty lipoproteins. Immunoaffinity columns with HB-22 (in the absence of Tween 20) showed an immunosorbent capacity of 80 mu g of apo A-I per m illigram of antibody, The immunosorbent capacity of HB-22 for apo A-I was similar in plasma samples from normolipidemic, hypercholesterolemi c, or hypertriglyceridemic patients. Comparative binding studies demon strated that compared with other available monoclonal apo A-I antibodi es, HB-22 had the greatest apparent affinity for binding to HDL, A com petitive ELISA developed by utilizing HB-22 could detect as little as 20 ng of apo A-I in the reaction mixture, The intra- and interassay CV s of the ELISA were 5.4% and 9.5%; respectively.