The idiotypic network: the murine MOPC315 anti-DNP system.

BALB/c mice were immunized against a monoclonal antiidiotypic antibody (Id 315.1.4) directed against the myeloma DNP-binding protein MOPC315 (IgA-lambda 2). This antibody is specific for an MOPC315 "private" idiotope, and the expression of this idiotope requires the interaction between MOPC315 heavy and lambda chains. Two categories of antibodies, able to combine with Id 315.1.4, were characterized in the sera of anti-Id 315.1.4 mice: (1) antibodies with a kappa light chain and without detectable anti-DNP function, and (2) antibodies with a lambda light chain and able to combine with DNP antigen. This observation suggests that the idiotypic network is not close-ended for a given idiotypic system but must be connected with other systems.