Second antibody clearance of /sup 131/I-labeled anti-carcinoembryonic antigen for improved tumor imaging
The authors have investigated the use of a second antibody (SA) directed against the radiolabeled primary anti-tumor antibody (PA) to enhance the clearance rate of the PA from the circulation and nontarget tissues. Administration of 50 or 250 ..mu..g of anti-goat IgG (SA) hr after the administration of 10 ..mu..g of /sup 131/I-goat anti-carcinoembryonic antigen antibody (PA) to hamsters bearing human colonic tumor xenografts resulted in a 5-fold reduction in the level of circulating PA after 4 hr in comparison to the control group only given /sup 131/I-PA. The percentage of PA in the blood decreased rapidly over 72 hr in animals given 250 ..mu..g of the SA, but at 50 ..mu..g of SA the level of activity in the blood after 24 hr was similar to the control. Tumor accretion was identical after 4 hr, but after 24 hr the animals given 250 ..mu..g of SA had 2-3 fold less PA in the tumor than either the control group or the 50 ..mu..g dose of SA. Tumor/nontumor ratios for all major organs but the spleen improved 6-8 fold within 48 hr after injection of 250 ..mu..g of the SA with tumor/blood ratios as high as 40:1. A SA dose of 50 ..mu..g resulted in a significantly higher tumor/blood ratio after only 4 hr; tumor/nontumor ratios at later times were similar to the control group. Tumors located in the hind legs were visible in all groups by imaging 24 hr after injection of the SA, but only the 250 ..mu..g dose of SA showed a significant reduction in total body activity. These results suggest that the SA approach may be used to reduce the total background radioactivity while maintaining tumor accretion of /sup 131/I-PA to allow for selective tumor imaging.
- Research Organization:
- Center for Molecular Medicine and Immunology at UMDNJ, Newark, NJ
- OSTI ID:
- 6644357
- Report Number(s):
- CONF-850611-
- Journal Information:
- J. Nucl. Med.; (United States), Vol. 26:5; Conference: 32. annual meeting of the Society of Nuclear Medicine, Houston, TX, USA, 2 Jun 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANTIBODIES
CLEARANCE
TISSUE DISTRIBUTION
CARCINOEMBRYONIC ANTIGEN
ANTIGEN-ANTIBODY REACTIONS
EXPERIMENTAL NEOPLASMS
ANTIGENS
ANIMAL TISSUES
BLOOD CIRCULATION
DIAGNOSIS
DIAGNOSTIC TECHNIQUES
DIAGNOSTIC USES
EMBRYONIC CELLS
HAMSTERS
IMAGES
INJECTION
IODINE 131
LEGS
SPLEEN
TIME DEPENDENCE
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
BODY AREAS
DAYS LIVING RADIOISOTOPES
DISTRIBUTION
INTAKE
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
LIMBS
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANS
RADIOISOTOPES
RODENTS
TISSUES
USES
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics