Idiotypic-anti-idiotypic antibody interactions in experimental radioimmunotargeting

Idiotypic-anti-idiotypic antibody interactions can be used in vivo to regul ate the serum levels of specific radiolabeled antibodies. Anti-idiotypic an tibodies can also be used as clearing agents for radiolabeled antibodies in radioimmunolocalization and radioimmunotherapy. The present study describe s the immunochemical interactions between the monoclonal idiotype (H7) and three generated monoclonal anti-idiotypic antibodies (alpha H7:1, alpha H7: 35, and alpha H7:38). An unexpected variability in complex formation could be demonstrated in vitro, revealing three different stable complex patterns , i.e., low molecular weight 1:1 complexes, ladder formation with oligomeri c, consecutively added constituents, and large linear polymeric complexes o f high molecular weight. Within 24 h, the anti-idiotypes were able to cause a significant decrease in total body radioactivity, and the antibody gener ating a ladder formation (alpha H7:38) was found to be the most efficient a t removing radiolabeled idiotypes from the circulation. It is concluded tha t monoclonal antiidiotypic antibodies may be valuable tools in improving ra dioimmunolocalization and radioimmunotargeting.