Quantitative determination of apolipoprotein B in bovine serum by radial immunodiffusion

1. In the present study we describe the first quantitative determination of apolipoprotein B (apo B) in bovine serum. 2. Immunosera and standard for radial immunodiffusion assay were raised using a purified apo B-containing lipoprotein obtained by ultracentrifugation and affinity chromatography. The assay working range was linear over the concentration of 4-70 mg/100 ml of protein of apo B standard. 3. Contrary to humans, bovine serum contains a low level of apo B-containing lipoproteins. The mean level of apo B in serum samples from cows at various stages of lactation was 16.0 +/- 0.6 mg/100 ml.