Electroimmuno- and immunonephelometric assays of apolipoprotein A-I by using a mixture of monoclonal antibodies

Clin Chem. 1988 Oct;34(10):2048-52.

Abstract

The use of mixtures of well-defined monoclonal antibodies may represent a step forward in the standardization of immunochemical assays. We developed and optimized working conditions for using such a mixture to determine apolipoprotein A-I in human sera by two independent techniques (electroimmuno- and immunonephelometric-assays). Six monoclonal antibodies, each addressed to distinct epitopes located at the surface of apolipoprotein A-I, were used in combination to permit a reproducible measurement of the protein, without prior delipidation of samples. Parallel standard curves for a high-density lipoprotein subfraction (HDL3, the primary standard) and a reference serum (the secondary standard) were obtained. Within- and between-run coefficients of variation were acceptable for both methods. Apolipoprotein A-I concentrations, as measured in 60 subjects selected to present a large range of apolipoprotein content by electroimmunoassay (y1) and immunonephelometric assay (y2) with monoclonal antibodies, compared well with those measured by the same techniques but with polyclonal antibodies (x): r1 = 0.96, r2 = 0.99; y1 = 1.19x - 0.11 g/L, y2 = 0.98x. Comparison of results obtained by electroimmunoassay and immunonephelometric assay performed with monoclonal antibodies was also good: r = 0.96; y2 = 1.08y1 + 0.13 g/L.

MeSH terms

  • Antibodies, Monoclonal*
  • Apolipoprotein A-I
  • Apolipoproteins A / blood*
  • Humans
  • Immunoelectrophoresis, Two-Dimensional
  • Lipoproteins, HDL / blood
  • Lipoproteins, HDL3
  • Nephelometry and Turbidimetry

Substances

  • Antibodies, Monoclonal
  • Apolipoprotein A-I
  • Apolipoproteins A
  • Lipoproteins, HDL
  • Lipoproteins, HDL3