Idiotype‐anti‐idiotype interactions and the control of the anti‐β(2→6) polyfructosan response in the mouse: specificity and idiotypy of anti‐ABPC48 anti‐idiotypic monoclonal antibodies

Seventeen hybridomas, secreting monoclonal anti-idiotypic antibodies (IDA) directed against the BALB/c ABPC48 idiotype, were isolated from one immunized BALB/c mouse. Several IDA also bind another Balb/c idiotype: UPC10. ABPC48 and UPC10 are both myeloma proteins with a beta (2 leads to 6)-polyfructosan (levan) specificity. The binding of every IDA to the ABPC48 idiotype can be completely inhibited by levan molecules, but at different concentrations. Mutual inhibition assays between the IDA made it possible to define six groups of IDA which bind at least three different idiotopes of ABPC48. Sixteen IDA have been studied by means of mouse anti-anti-idiotypic antibodies (Ab3) directed against two of them, IDA3 and IDA10. Anti-IDA3 Ab3 recognize idiotopes particular to IDA3 which are not found on other monoclonal anti-idiotypic antibodies (Ab2). Anti-IDA10 AB3 cross-reacts with several monoclonal Ab2, including Ab2 with different spectrotypes belonging or not to the same isotype and Ab2 with different specificities for the ABPC48 idiotype. Some IDA10 idiotopes are present in the polyclonal anti-ABPC48 antibody response of BALB/c, A/J and CBA mice showing that they are recurrent and that their expression is not linked to a particular Igh-C haplotype. In contrast, IDA3 idiotopes are not detected in the same anti-ABPC48 antisera.