DETERMINATION OF ALPHA-FETOPROTEIN CONCENTRATION BASED ON LIQUID-PHASE BINDING ASSAY USING ANION-EXCHANGE CHROMATOGRAPHY AND SULFATED PEPTIDE INTRODUCED ANTIBODY

A new immunoassay for alpha-fetoprotein based upon liquid-phase bindin g reactions is described. In this procedure, a sample that contains al pha-fetoprotein is mixed with a solution of two anti-alpha-fetoprotein monoclonal antibodies complexed with peroxidase and sulfated peptide, respectively. After incubation, immune complex is separated from othe r components by anion exchange column chromatography. Immune complex i s quantified using fluorometric detection by peroxidase enzymatic acti vity. Peroxidase activity correlated with a alpha-fetoprotein with a 1 :1 relationship. The stoichiometric immunoreaction allowed a large ana lytical range (0.4-7500 ng/ml) with a linear dose-response relationshi p, high sensitivity and good precision. Endogenous substances did not interfere with assay performance. Assay results showed good correlatio n with other established methods. These results indicate that the meth od is useful for clinical alpha-fetoprotein determinations. (C) 1998 E lsevier Science B.V. All rights reserved.