IMAGING WITH I-131-LABELED MONOCLONAL-ANTIBODIES TO A HIGH-MOLECULAR-WEIGHT MELANOMA-ASSOCIATED ANTIGEN IN PATIENTS WITH MELANOMA - EFFICACY OF WHOLE IMMUNOGLOBULIN AND ITS F(AB')2 FRAGMENTS

  • 1 January 1985
    • journal article
    • research article
    • Vol. 45  (7) , 3378-3387
Abstract
In vitro experiments selected optimal conditions to radiolabel with 131I the whole Ig and F(ab'')2 fragments of the monoclonal antibody (MoAb) 225.28S to a high MW melanoma-associated antigen (HMW-MAA). Injection of the radiolabeled whole Ig and F(ab'')2 fragments of the MoAb 225.28S into 8 patients with melanoma resulted in the accumulation of radioactivity in 10 of 18 metastases. This localization is specific because of the close relationship between detection of HMW-MAA in lesions by immunohistochemical techniques and outcome of immunoscintography and because of the different distribution in tumors and adjacent tissues of radiolabeled F(ab'')2 fragments of MoAb 225.28S compared with 99mTc-pertechnetate and with radiolabeled F(ab'')2 fragments of MoAb 4C4 to hepatitis B surface antigen. F(ab'')2 fragments are superior to whole Ig to perform immunoscintigraphy, since they markedly reduce the background in bone marrow, liver and spleen. The sensitivity of the procedure allows the detection of lesions with a diameter of at least 1.5 cm and is influenced by the level of the HMW-MAA in lesions and by their anatomical site.