Monoclonal anti-azobenzenearsonate antibodies expressing the cross-reactive idiotype: immunochemical studies show that all idiotypic determinants reside on a single molecule.

Cell lines that secreted antibodies to the hapten azobenzenearsonate (ABA) were established by hybridization of immune A/J spleen cells to the non-secreting myeloma, NS-1. Solid-phase radioimmunoassays (RIA) were developed for rapid screening of hybridoma supernatants to detect antibodies to ABA and to detect antibodies bearing the ABA cross-reactive idiotype (CRI). Hybrid clones secreting both CRI+ and CRI-- anti-ABA antibodies were obtained. The supernatant from one clone (7-13) strongly inhibited binding of iodinated anti-idiotype serum in a competitive RIA. This clone expressing the CRI produced immunoglobulin of the IgG2a subclass. Solid-phase absorption of anti-idiotype serum followed by competitive radioimmunoassay analyses revealed that all the idiotypic determinants recognized by anti-idiotype serum reside on this monoclonal antibody.