Lectin affinity electrophoresis of alpha-fetoprotein detected by immunoenzymatic and chemiluminescent amplification followed by direct scanning.

Microdetermination of alpha-fetoprotein (AFP) glycoforms by lectin affinity electrophoresis followed by chemiluminescence reaction using horseradish peroxidase (POD) or alkaline phosphatase (ALP) in antibody-affinity blotting was developed. The intensity of chemiluminescence obtained by ALP was greater than that by POD; however, the coefficient of variation with POD was less than that with ALP. The optimized sensitivity of the chemiluminescence method with POD was two times that of the most sensitive colorimetric method currently available in terms of the chemiluminescence intensity per unit AFP concentration. The lower detection limit by the chemiluminescence method with POD (0.5 ng/ml) was much lower than that by the colorimetric method (3 ng/ml). Both methods gave identical percentages of lentil lectin- and erythroagglutinating phytohemagglutinin-reactive minor bands using a serum with 52 ng/ml AFP. This result indicates that microdetermination of AFP glycoforms by chemiluminescence after lectin-affinity electrophoresis was more sensitive than currently available methods and that it is potentially useful for clinical application.