Indium-111 labeled monoclonal antibodies (Ab): The effect of DTPA conjugation on the Ab activity and tissue distribution
Monoclonal antibodies (Ab) to human ..cap alpha..-fetoprotein (AFP) were conjugated with diethylenetriaminepentaacetic acid (DTPA) using cyclic DTPA anhydride and the obtained conjugates, DTPA-Ab, were labeled with In-111. The effect of DTPA conjugation on the affinity constant and the maximum binding capacity of Ab was evaluated by radioimmunoassay and Scatchard plot analysis and In-111 labeled DTPA-Ab were used for the radioimmunodetection of tumor. Ab containing 1.0 DTPA molecule per Ab showed almost full retention of both the affinity constant and the maximum binding capacity. Then, 40 ..mu..Ci of In-111 labeled DTPA-Ab were injected intravenously to nude mice bearing AFP-producing human testicular tumor and the resulted were compared with I-131 labeled Ab. Scintigraphy clearly revealed transplanted tumor. Localization of In-111 labeled DTPA-Ab was significantly higher than I-131 labeled Ab. Tumor to blood ratio obtained at 4 days after injection was 2.59 with In-111 labeled DTPA-Ab compared to 0.99 with I-131 labeled Ab. When more than 1.9 DTPA molecules were incorporated per Ab, the maximum binding capacity decreased, although the affinity constant was less affected. These In-111 labeled DTPA-Ab caused significantly higher liver accumulation. These results indicate that In-111 labeled DTPA-Ab at a cojugated DTPA to Ab molar ratio of 1.0 may be superior to I-131 labeled Ab for tumor imaging, but the maximum binding capacity and tissue distribution of In-111 labeled DTPA-AB are greatly dependent upon the number of DTPA molecules incorporated per Ab molecule.
- Research Organization:
- Kyoto Univ., Kyoto
- OSTI ID:
- 7089623
- Report Number(s):
- CONF-840619-; TRN: 87-008839
- Journal Information:
- J. Nucl. Med.; (United States), Vol. 25:5; Conference: 31. annual meeting of the Society of Nuclear Medicine, Los Angeles, CA, USA, 5 Jun 1984
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DTPA
DIAGNOSTIC USES
LABELLING
INDIUM 111
MICE
NEOPLASMS
MONOCLONAL ANTIBODIES
BIOCHEMICAL REACTION KINETICS
DIAGNOSIS
IMAGE PROCESSING
INDIUM 131
INJECTION
PROTEINS
RADIOIMMUNOASSAY
TRACER TECHNIQUES
AMINO ACIDS
ANIMALS
ANTIBODIES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CHELATING AGENTS
DAYS LIVING RADIOISOTOPES
DISEASES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
IMMUNOASSAY
IMMUNOLOGY
INDIUM ISOTOPES
INTAKE
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PROCESSING
RADIOASSAY
RADIOIMMUNOLOGY
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
REACTION KINETICS
RODENTS
SECONDS LIVING RADIOISOTOPES
USES
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics