Semi-automated enzyme-linked immunosorbent assay (ELISA) for the quantification of apolipoprotein B using monoclonal antibodies

A semi-automated competitive, double-antibody, solid-phase enzyme-linked immunosorbent assay for apolipoprotein B (Apo B) has been developed which utilizes microtiter plates with commercially available monoclonal antibodies and alkaline phosphatase-conjugated second antibody. The working range of the assay is 20–200 ng. The concentration of plasma Apo B was 0.88 ± 0.20 g/l ( n = 40) for a random sample of normal adults. The correlation coefficient for this assay, compared to a radial immunodiffusion assay, was 0.95 (slope = 1.13, intercept = −15). The quantification of the samples was not influenced by freezing and thawing, storage at −20°C for up to 9 mth, or the lipoprotein particle on which the Apo B was present. The method is suitable for measurement of apolipoprotein B in either normal or pathological plasma, lipoprotein density classes, and is sensitive enough to quantify Apo B in cell biological and molecular biological investigations.