A NOVEL ANTI-SEMINOMA MONOCLONAL-ANTIBODY (M2A) LABELED WITH TC-99M -POTENTIAL APPLICATION FOR RADIOIMMUNOSCINTIGRAPHY

Objective To study the potential usefulness of monoclonal antibody (mA b) M2A specific for seminoma to image tumour nodules in a preclinical nude mouse model. Materials and methods MAb M2A was labelled with tech netium-99m (Tc-99m) following reduction and was administered intraperi toneally to nude mice bearing subcutaneous HEY cell xenografts against which the antibody was originally raised, Biodistribution and gamma s cintigraphy studies were performed 24 h after administration of Tc-99m -M2A. Results Biodistribution studies showed specific targeting of Tc- 99m-M2A to HEY tumours in comparison with control mAb Tc-99m-6E8 and T c-99m-2G3 which do not bind to HEY cells. Subcutaneous HEY cell tumour s (0.5-1.0 g) were successfully imaged using gamma-scintigraphy follow ing administration of Tc-99m-M2A. Conclusion The results of this study indicate the potential usefulness of Tc-99m-M2A as a clinical reagent for imaging seminoma metastases.