Imaging of human tumor xenografts in nude mice with radiolabeled monoclonal antibodies. Limitations of specificity due to nonspecific uptake of antibody

Journal Article · Mon Oct 01 04:00:00 EDT 1984 · Cancer (Philadelphia); (United States)

DOI:https://doi.org/10.1002/1097-0142(19841001)54:7<1318::AID-CNCR2820540715>3.0.CO;2-J· OSTI ID:6451158

Mann, B D; Cohen, M B; Saxton, R E; Morton, D L; Benedict, W F; Korn, E L; Spolter, L; Graham, L S; Chang, C C; Burk, M W

To determine if in vivo binding specificities of monoclonal antibodies to tumor nodules would reflect in vitro antibody specificities as determined by radioimmunoassay, two monoclonal antibodies were selected for imaging of human tumor xenografts in nude mice. By in vitro radioimmunoassay, antibody 436 binds to the M20 melanoma cell line, but not to the P3 carcinoma cell line; antibody 44 binds to P3 but not to M20. Both antibodies are IgG1 isotypes. Nude mice bearing an M20 melanoma in one flank and a P3 carcinoma in the other were injected intravenously with 5 to 25 micrograms of each antibody labeled with either I-125 or I-131; in separate animals the labels were reversed. Animals were imaged daily with a scintillation camera equipped with a pinhole collimator. On day 6 the animals were sacrificed, and binding of the antibodies to the tumors and normal tissue were compared. Antibody 436 had up to a two-fold binding advantage in vivo for the melanoma, whereas antibody 44 had up to a two-fold binding advantage for the carcinoma, thus confirming the in vitro specificities of each. However, imaging on day 4 and computer analysis of percent radioactivity in the tumors showed that tumor images were related directly to tumor size and relatively uninfluenced by antibody specificity. Thus, even though antibody specificity can be demonstrated by differential tissue counting, imaging of tumor deposits appears to involve a nonspecific phenomenon that is largely dependent upon tumor weight.

• Research Organization: Surgical Service, Veterans Administration Medical Center, Sepulveda
• OSTI ID: 6451158
• Journal Information: Cancer (Philadelphia); (United States), Journal Name: Cancer (Philadelphia); (United States) Vol. 54:7; ISSN CANCA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMAL CELLS
ANIMALS
ANTIBODIES
CHEMICAL BONDS
DIAGNOSTIC USES
DISEASES
GRAFTS
IMAGES
IN VITRO
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MELANOMAS
MICE
MONOCLONAL ANTIBODIES
NEOPLASMS
RADIOASSAY
RADIOIMMUNOASSAY
RODENTS
TRACER TECHNIQUES
TRANSPLANTS
TUMOR CELLS
USES
VERTEBRATES