Targeting of human glioma xenografts in vivo utilizing radiolabeled antibodies
- Johns Hopkins Oncology Center, Baltimore, MD (USA)
Radiolabeled antibodies provide a potential basis for selective radiotherapy of human gliomas. We have measured tumor targeting by radiolabeled monoclonal and polyclonal antibodies directed against neuroectodermal and tumor-associated antigens in nude mice bearing human glioma xenografts. Monoclonal P96.5, a mouse IgG2a immunoglobulin, defines an epitope of a human melanoma cell surface protein, and specifically binds the U-251 human glioma as measured by immunoperoxidase histochemistry. 111In-radiolabeled P96.5 specifically targets the U-251 human glioma xenograft and yields 87.0 microCuries (microCi) of tumor activity per gram per 100 microCi injected activity compared to 4.5 microCi following administration of radiolabeled irrelevant monoclonal antibody. Calculations of targeting ratios demonstrate deposited dose to be 11.6 times greater with radiolabeled P96.5 administration compared to irrelevant monoclonal antibody. The proportion of tumor dose found in normal organs is less than 10%, further supporting specific targeting of the human glioma xenograft by this antibody. Monoclonal antibody ZME018, which defines a second melanoma-associated antigen, and polyclonal rabbit antiferritin, which defines a tumor-associated antigen, demonstrate positive immunoperoxidase staining of the tumor, but comparatively decreased targeting. When compared to the 111In-radiolabeled antibody, 90Y-radiolabeled P96.5 demonstrates comparable tumor targeting and percentages of tumor dose found in normal organs. To test the therapeutic potential of 90Y-radiolabeled P96.5, tumors and normal sites were implanted with miniature thermoluminescent dosimeters (TLD). Seven days following administration of 100 microCi 90Y-radiolabeled P96.5, average absorbed doses of 3770, 980, 353, and 274 cGy were observed in tumor, liver, contralateral control site, and total body, respectively.
- OSTI ID:
- 6870389
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics; (USA), Journal Name: International Journal of Radiation Oncology, Biology and Physics; (USA) Vol. 18:6; ISSN IOBPD; ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMALS
ANTIBODIES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
DISEASES
DOSES
DOSIMETRY
ELECTRON CAPTURE RADIOISOTOPES
EXPERIMENTAL NEOPLASMS
GLIOMAS
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IMMUNOTHERAPY
INDIUM 111
INDIUM ISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
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MAMMALS
MAN
MEDICINE
MICE
MINUTES LIVING RADIOISOTOPES
MONOCLONAL ANTIBODIES
NEOPLASMS
NUCLEAR MEDICINE
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
PRIMATES
RADIATION DOSES
RADIOIMMUNOLOGY
RADIOIMMUNOTHERAPY
RADIOISOTOPES
RADIOLOGY
RADIOTHERAPY
RODENTS
THERAPY
THERMOLUMINESCENT DOSIMETRY
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YTTRIUM 90
YTTRIUM ISOTOPES