BINDING OF HOMOLOGOUS AND HETEROLOGOUS ISOLUMINOL-LABELED AND ENZYME-LABELED PROGESTERONE CONJUGATES TO MONOCLONAL-ANTIBODIES

The binding of three different progesterone-isoluminol and three diffe rent progesterone-enzyme (HRP) conjugates to monoclonal antibodies aga inst progesterone-7-carboxy thioether-bovine serum albumin (clone 2H4) and progesterone-11-hemisuccinate-bovine serum albumin (clone 1E11) w as compared. The isoluminol labels were covalently bound to progestero ne via hemisuccinate bridges at carbon atoms 3, 7 or 11. The enzyme la bels were covalently attached to the steroid using a carboxymethyl-ami nocaproic acid bridge at carbon atom 3 or a hemisuccinate bridge at ca rbon atom 11. The influence of several factors on the binding between antibodies and conjugates and on the slopes of the calibration curves was studied. Considerable differences in the binding of the label and in the shape of the curves between both antibodies was observed. In en zyme immunoassay, using clone 1E11, the binding of the progesterone-en zyme conjugate and the shape of the curves was governed by the presenc e in the reaction mixture of the antibodies in liquid or solid-phase c onditions.