Regulation of the BALB/c anti-p-azophenylarsonate antibody response by monoclonal anti-idiotype. I. Anti-idiotope fine specificity.

Five monoclonal anti-idiotype antibodies were prepared against the IgG1 monoclonal antibody, 5AF6, the prototype molecule representing the BALB/c 5AF6 idiotype family of antibodies specific for the p-azophenylarsonate (Ar) hapten. Three were of BALB/c origin and two were derived from allotype congenic strain CB.20. All five anti-idiotopes (id) reacted with the 5AF6 immunogen but not with four other BALB/c anti-Ar sharing other id with 5AF6. Four of the five showed some reactivity with three monoclonal anti-Ar derived from A strain mice that represent a minor component of the anti-Ar from that strain. Reactivity patterns of these anti-id indicated that all five reacted with different id on the 5AF6 molecule, yet all five were sufficiently close to the Ar-binding site for their binding to be blocked by the Ar hapten alone. Furthermore, all five anti-id could compete with each other for binding to 5AF6, indicating that the five id detected by these anti-id were in close proximity. Four of the five anti-id reacted with id produced by conformations requiring both the appropriate heavy and light chains. The fifth anti-id reacted with a heavy chain id stabilized by the presence of any light chain. The implications of such a diverse anti-id response against a single antibody molecule on anti-id network interactions are discussed.