Immune response induced by a single or several syngeneic monoclonal antiABPC48 antiidiotypic antibodies: No predominant coexpression of ABPC48 idiotopes

Abstract

BALB/c mice were immunized with monoclonal BALB/c antibodies IDA 10, IDA 16 and IDA 17 raised against the BALB/c ABPC48 myeloma protein. Several procedures of immunization—copolymers with lipopolysaccharide or keyhole limpet hemocyanin, simultaneous or sequential injections of different IDAs—were performed in an attempt to orient the immune response towards the production of ABPC48-like idiotypes. We used a binding assay which identifies two idiotopes on the same molecule to measure the population of antibodies induced in these responses. The expression of ABPC48 cross-reactive idiotypes in immune sera was analyzed. The results show that, with all immunization protocols, immune responses to different monoclonal antiidiotypic antibodies are mostly independent of each other: the coexpression of ABPC48 idiotopes, either private or recurrent on the induced antibodies, is rarely found; it makes it difficult to discriminate by a serological approach between cross-reactive idiotypes and anti-antiidiotypic antibodies. We discuss the interest of combining molecular and serological approaches to identify these two populations of antibodies.