A non-competitive solid-phase radioimmunoassay for human aldolase A

Abstract

A solid-phase, non-competitive radioimmunoassay for aldolase A in human serum has been developed. Human aldolase A was purified from muscle, and specific antisera to the purified aldolase A were obtained from chickens. Specific IgG anti-human aldolase A was purified by affinity chromatography. Disposable polypropylene plates were coated with specific IgG antibody and used for radioimmunoassay with 125I-specific IgG antibody to aldolase A. The non-specific binding was minimized by saturating the binding sites of the plates with 2% ovalbumin in 0.1% Tween 20. This radioimmunoassay is specific for the aldolase A subunit, with no cross-reactivity with human aldolase B subunit or homopolymeric human aldolase C (C 4). The serum aldolase A immunoreactivities of 33 normal subjects ranged from 124 to 212 ng/ml with a mean of 178 ±41 ng/ml (±2 SD). Ninety-three patients' sera were assayed with both a solid-phase non-competitive radioimmunoassay and a competitive double antibody radioimmunoassay developed in our laboratory and the results showed a high degree of correlation ( r = 0.912; p < 0.001). Rapidity and simplicity of the solid-phase assay makes it superior to other methods for the measurement of serum aldolase isozymes.