Evaluation of the immunoreactive fraction of an anti-tumour monoclonal antibody

Br J Cancer Suppl. 1990 Jul;10:15-7.


Over a period of approximately 1 year, the immunoreactivity of the anti-ovary carcinoma MAb MOv18 was evaluated after radiolabelling with 125I on two different ovarian carcinoma cell lines, OvCa432 and IGROV1. A high variability of the immunoreactive values was observed by analysing different preparations of radiolabelled MOv18 (from 12 to 21% on OvCa432 and from 22 to 56% on IGROV1) and by using the same radiolabelled preparation (12% on OvCa432 and 51% on IGROV1). Since the variability could be due to the target cells, we set up an alternative binding assay using the anti-idiotypic MAb anti-Id18.1 directed against a private idiotype closely associated with the MOv18 paratope. Three different experiments carried out with the anti-idiotypic MAb gave reproducible results with an immunoreactive range from 71 to 83%. A direct comparison between the reactivity of the same 125I-MOv18 preparation on anti-Id18.1 and on IGROV1 confirmed the higher value of the immunoreactive fraction estimated on the more homogeneous anti-idiotypic reagent (71%), rather than on the tumour cells (56%). These data suggest that anti-idiotypic MAbs could represent suitable reagents for the evaluation of the immunoreactivity of an antibody preparation after radiolabelling and before in vivo administration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Anti-Idiotypic
  • Antibodies, Monoclonal / immunology*
  • Evaluation Studies as Topic
  • Humans
  • Iodine Radioisotopes
  • Neoplasms / immunology*
  • Tumor Cells, Cultured


  • Antibodies, Anti-Idiotypic
  • Antibodies, Monoclonal
  • Iodine Radioisotopes