Generation of monoclonal anti-digoxin antibodies

Functional antagonism by a monoclonal antibody to digoxin in a test system of cultured rat heart myocytes

A monoclonal antibody with a high affinity for digitoxin (KA = 0.50 nM) and digoxin (KA = 0.55 nM) was produced by somatic cell fusion. This antibody, designated 2A3(47), displayed little cross reactivity with other glycosides. In cultured rat heart myocytes, 2A3(47), antagonized the positive chronotropic effect exerted by digitoxin but did not alter that of ouabain. Our results suggest that this monoclonal antibody may prove to be useful in treating digoxin and digitoxin intoxication.

An anti-digoxin monoclonal antibody seems to express more than one functional paratope

An anti-digoxin monoclonal antibody (mAb 4G3) has been produced and characterized with respect to its fine specificity and affinity. In an independent series of experiments anti-idiotypic monoclonal antibody (mAb 7G9) was selected which reacted with the antigen-binding center of an anti-human chorionic gonadotropin monoclonal antibody (anti-hCG mAb 1B10). In detailed studies on its binding characteristics it has been shown that mAb 4G3 binds to an anti-idiotypic monoclonal antibody mAb 7G9 in solution. Western blotting experiments showed that mAb 4G3 reacted against antiidiotypic antibody under non-reducing conditions, only. Moreover, mAb 4G3 has been shown to express self-binding properties. Absorption with saturating amounts of its specific hapten, i.e. digoxin, did not change the binding of mAb 4G3 to anti-idiotypic antibody and its self-binding ability. It is speculated on the basis of these data that mAb 4G3 possesses more than one functional paratope.

Conformation-sensitive immunoassay: optimisation, validation and evaluation

A conformation-sensitive immunoassay (CSI) has recently been developed (Pfund and Bourdage, 1990). This paper describes the optimal laboratory protocol which makes this method useful as an early screening procedure for conformation-sensitive monoclonal antibodies. The method was validated with a panel of 12 monoclonal antibodies. Results from our experiments confirm that this variant of CSI can be applied in the analysis of purified proteins and glycoproteins, as well as complex mixtures of antigens.