Rapid induction of anti-idiotypic responses to unmodified monoclonal antibodies from syngeneic mice following primary immunization.

A single foot-pad immunization in adjuvant of BALB/c mice with non-modified BALB/c monoclonal antibodies (HyHEL 5, 9 and 10) specific for hen egg lysozyme permitted isolation of anti-idiotypic monoclonal antibodies 10 days later. An evaluation of different screening tests revealed that antibodies were detected more easily by isotype-specific or direct binding assays than by cross-linking ELISA procedures. These results were confirmed by a direct cell-binding assay on B cells transgenic for one of the immunizing antibodies. The use of these cells also permitted an evaluation of the ability of these antibodies to inhibit antigen binding under conditions in which the target antibody, in its cell-surface configuration, is minimally modified by potential artifacts induced by purification or fixation to a solid support. This study demonstrates that anti-idiotypic responses to anti-protein antibodies may be rapidly generated in syngeneic animals.