| Abstract: | Antibodies that define the idiotypic marker 104E-MPC11 were purified from rabbit anti-M104E sera. The expression of this marker was searched for in a panel of representative myeloma and hybridoma proteins differing in antigen-binding specificities and idiotype expression. By radioimmune competition assays, the marker was distinguished from the IdX Dex idiotype of BALB/c alpha 1-3 dextran-binding proteins (alpha 1-3 Dex-BP) in that it was expressed on both IdX Dex-positive and IdX Dex-negative proteins on the one hand, and on A/J p-azophenylarsonate-binding proteins (Ar-BP) on the other. Among the later, six of eight of the proteins also expressed the major cross-reactive idiotype (CRI). The marker was expressed weakly or not at all on A/J Ar-BP, which did not express the CRI, as well as on a number myeloma and hybridoma proteins of different antigen-binding specificities, and normal IgG. The marker was localized in VH, but its full expression required the light chain, and was influenced by quaternary structure. |
