Syngeneic anti-idiotypic antibody prevents localization of a murine monoclonal antibody in human tumour xenografts.

BALB/c mice were immunized against syngeneic mouse monoclonal antibody (Mab) 791T/36 to produce anti-idiotypic antibody. To examine the effect of this antibody on tumour localization of the Mab, serum from these mice was transferred to nude mice with human tumour xenografts and distribution was studied with I-125 labelled Mab. Serum containing anti-idiotypic antibody prevented tumour localization of the Mab. This finding has implications for the clinical use of human or humanized Mab since, if these evoke anti-idiotypic antibody, this alone may be sufficient to prevent tumour targeting.