ANTI-IDIOTYPES TO MONOCLONAL ANTI-H-2 ANTIBODIES .1. CONTRIBUTION OF ISOLATED HEAVY AND LIGHT-CHAINS TO IDIOTYPE EXPRESSION

Anti-idiotypic sera were produced by immunization of miniature swine with affinity-purified monoclonal anti-H-2Kk mouse antibodies. The purified anti-idiotypic antibodies obtained by this immunization recognized unique determinants on each monoclonal anti-H-2Kk immunogen and were not broadly cross-reactive with other anti-H-2Kk antibodies. These reagents were used to examine the expression of idiotype on isolated H and L chains and on reassociated Ig molecules. Minor populations of idiotope(s) could be detected by a direct binding radioimmune assay on isolated H chains and on isolated L chains. The predominant idiotope(s) were expressed only on native Ig and on isolated H chains. The expression of these H-chain idiotopes was found to be specifically augmented by the addition of homologous L chains. Reassociation of H chains with L chains from a different anti-H-2Kk monoclonal antibody diminished idiotype expression. A model for the molecular interactions occurring between these molecules is proposed on the basis of these results. The nature of these interactions may also have implications for the analysis of the basis of idiotype expression on anti-major histocompatibility complex T cell receptors.