Monoclonal antibodies against common and Igk-1a allotypic determinants of rat immunoglobulin kappa chain constant domain.

SJL/J mice were immunized with polyclonal rat Ig light chains of two allotypes and immune spleen cells were fused with P3-Ag8.653 myeloma cells. 17 cell populations producing antirat Ig AB were cloned. Four clones, 1G9, L3E8, L2B2 and L2C5 have been characterized in detail. All MABs are of the IgG1, kappa isotype. Using monoclonal rat kappa chains it was demonstrated that all the AB react with rat Ig kappa chains. Further localization of antigenic determinants was performed using isolated L chain C domain. It was shown that all MABs are directed against C domain epitopes. L2C5 MAB binds selectively to August rat L chains, thus showing specificity for Igk-1a determinants. The remaining three clones bind equally well to L chains of different allotypes, but 1G9 clone binds preferentially to isolated L chains as compared to intact IgG molecules.