Relationship between in vitro binding activity and in vivo tumor accumulation of radiolabeled monoclonal antibodies
The relationship between in vitro cell binding and in vivo tumor accumulation of radiolabeled antibodies was studied using /sup 125/I- and /sup 111/In-labeled monoclonal antibodies to human osteosarcoma, and a human osteosarcoma xenograft (KT005) in nude mice. Three monoclonal antibodies--OST6, OST7, and OST15--raised against human osteosarcoma recognize the same antigen molecule. Although the binding of both /sup 125/I- and /sup 111/In-labeled OST6 to KT005 cells was higher than that of radiolabeled OST7 in vitro, /sup 125/I-labeled OST6 showed a faster clearance from the circulation and a lower accumulation in the transplanted tumor than /sup 125/I-labeled OST7. In contrast to the radioiodinated antibodies, the in vivo tumor accumulation of /sup 111/In-labeled OST6 was higher, although not significantly, than that of /sup 111/In-labeled OST7. OST15 showed the lowest binding in vitro, and its in vivo tumor localization was also lower than the others. The discrepancy in tumor uptake between OST6 and OST7 labeled with either /sup 125/I or /sup 111/In may have been a result of differing blood clearance. These results suggest that binding studies can be used to exclude from in vivo use those antibodies which show very poor binding in vitro, while in vivo serum clearance may be a better test for choosing antibodies with similar binding.
- Research Organization:
- Kyoto Univ. (Japan)
- OSTI ID:
- 5201792
- Journal Information:
- J. Nucl. Med.; (United States), Vol. 29:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
MONOCLONAL ANTIBODIES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL ACCUMULATION
OSTEOSARCOMAS
RADIOIMMUNOTHERAPY
ANTIGENS
BLOOD-PLASMA CLEARANCE
EXPERIMENTAL NEOPLASMS
IN VITRO
INDIUM 111
IODINE 125
MAN
MICE
TISSUE DISTRIBUTION
TRANSPLANTS
ANIMALS
ANTIBODIES
BETA DECAY RADIOISOTOPES
CLEARANCE
DAYS LIVING RADIOISOTOPES
DISEASES
DISTRIBUTION
ELECTRON CAPTURE RADIOISOTOPES
IMMUNOLOGY
INDIUM ISOTOPES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MEDICINE
MINUTES LIVING RADIOISOTOPES
NEOPLASMS
NUCLEAR MEDICINE
NUCLEI
ODD-EVEN NUCLEI
PRIMATES
RADIOIMMUNOLOGY
RADIOISOTOPES
RADIOLOGY
RADIOTHERAPY
REACTION KINETICS
RODENTS
SARCOMAS
SKELETAL DISEASES
THERAPY
VERTEBRATES
550604* - Medicine- Unsealed Radionuclides in Therapy- (1980-)