Generation of monoclonal anti-digoxin antibodies.

Anti-digoxin monoclonal antibodies are a useful model for basic immunochemical studies, for investigation of endogenous digoxin-like substances and in immunoassay for cardiac glycosides. The complete phenotypic characterization is a requisite for the selection of antibodies with desired binding parameters for different purposes. Twenty-two high-affinity monoclonal antibodies specific for digoxin were obtained in two fusion experiments. Treatment of antigen-antibody complex with potassium thiocyanate (KSCN) and absorption ELISA were used for the selection of high-affinity antibodies at the earliest stages of hybridoma growth. The true affinity constants of selected antibodies were determined in ELISA. They had proven to vary between 10(-7) and 10(-10) M. The fine specificity of 21 anti-digoxin monoclonal antibodies was determined by cross-reactivity experiments with 25 structurally related compounds. Cardiac glycosides, digoxin metabolites, endogenous steroids and spironolactone were used in the elucidation of the antigenic recognition pattern of antibodies. The elucidation of the binding characteristics of anti-digoxin monoclonal antibodies makes possible the selection of antibodies possessing binding characteristics appropriate for a wide range of designations.