IMMUNOSCINTIGRAPHY OF HUMAN NEUROBLASTOMA XENOGRAFTED IN NUDE-MICE USING A PANEL OF I-125 LABELED MONOCLONAL-ANTIBODIES

Neuroblastoma is the most frequent tumour of the childhood under the a ge of 5. The staging and the follow up are achieved by MIBG scintigrap hy, considered as the method of reference, but sometimes difficult to interprete. The availability of monoclonal antibodies against the gang lioside GD2, expressed on the cell membrane of neuroblastoma and neuro -endocrine cancers offers novel tools that deserve to be carefully exp lored. We investigated four mouse monoclonal antibodies (3 IgG3: BW704 , 7A4, 60C3, and the IgG1 variant of BW704: MAK704), on nude mice xeno grafted with a human neuroblastoma (REM). Sixty one nude mice were inc luded. The three former MAbs provided tumour imaging, the best results being obtained with BW704, followed by 7A4 and 60C3. MAK704 was disap pointing. A control antiphosphorylcholine antibody (P51-1) did not giv e any tumour image in the three tested mice. Scintigraphy ratios tumou r/liver and tumour/muscle reached 20 and 100 with BW704, respectively, on the 10th day. Good imaging quality was already obtained from the 2 4th h. The tumour uptake, calculated from radioactivity countings of r esected samples, reached 22 +/- 3% of injected dose per gramme. These results let us hope that these antibodies could also provide highly co ntrasted images in humans and could open the way for therapeutic appli cations.