Characterization of anti-idiotypic antibodies and their use as probes for determination of shared idiotopes expressed on murine and human IgE anti-rye I antibodies

Abstract

This study describes the production and characterization of rabbit anti-idiotypic antibodies (anti-ID Abs) against three idiotypes of three mAbs with different specificities. The anti-ID Abs were rendered idiotype specific by appropriate adsorption. Binding of labelled mAb to homologous anti-ID Ab bound to a polystyrene matrix was completely inhibited when the same mAb was added. In contrast, addition of other mAbs sharing the same isotype and the same light chain but with different specificity did not affect the binding reaction. Each anti-ID Ab inhibited completely and selectively the reaction between the allergen and the homologous mAb idiotype. Labelled rye I binding to a given polystyrene-bound mAb idiotype was completely blocked if the relevant anti-ID Ab was used as an inhibitor. Murine polyclonal anti-rye I antisera inhibited the reaction between all three mAbs and the antigens, as well as the reaction between all three mAb idiotypes and their homologous anti-ID Abs. On another hand, goat polyclonal anti-rye I antisera only inhibited the reaction between the mAbs and the antigens. These results suggest that the anti-ID Abs produced are directed against idiotopes located within the paratopes and such idiotopes are shared by murine monoclonal and polyclonal Abs. Human rye I-specific IgE and murine anti-rye I mAbs could share common idiotopes, since human IgE binding to the antigen was inhibited by the anti-ID Abs. These observations imply structural similarity in the V gene coding for the variable region of the antibody of two different species.