IMMUNOGENICITY AND ANTIGENICITY OF IMMUNOGLOBULINS .12. INTACT LIGHT CHAIN AND HEAVY-CHAIN ISOTYPE-RESTRICTED VK-ASSOCIATED EPITOPES

Abstract

Immunization with intact IgG allowed the isolation of 4 hybridomas producing antibodies recognizing epitopes expressed within subpopulations of human .kappa. L chains unrelated to known polymorphisms (Km) and previously defined V-region subgroups. The V-region-associated epitopes recognized are conformation-dependent, being expressed on intact L chain but not on isolated VK or CK fragments. The frequency of expression within paraprotein panels of different H chain isotypes varied between individual antibodies. An epitope recognized by B2A6, expressed by > 85% IgGK paraproteins, was not represented in 16 IgM paraproteins tested. This suggests that association of VK with .mu. chains does not result in display of the epitope recognized, or alternatively, that selective association between VK and CH gene products occurs. These data contrast with the reactivity of other monoclonal antibodies for CK epitopes which were reactive with isolated CK fragments, and for all .kappa.-bearing paraproteins, regardless of H chain isotypes.