Coupling of the 99mtechnetium-nitrido group to monoclonal antibody and use of the complexes for the detection of tumors in mice
The in vivo detection of tumors by immunoscintigraphy using /sup 99m/Tc labelled monoclonal antibodies (MoAb) was explored in this study. A simple method for the labelling of microgram quantities of MoAb with /sup 99m/Tc based on the substitution reaction of MoAb and /sup 99m/TcNCl/sub 4//sup -/ is described. The selective activity of the /sup 99m/technetium-nitrido-MoAb (/sup 99m/TcN-MoAb) complexes was proved in vitro by a binding assay with different target cells. The /sup 99m/TcN-MoAb complexes were shown to bind reactive cells up to 20 times more avidly than nonreactive cells. The specificity of the /sup 99m/TcN-MoAb complexes was shown in vivo. (C57BL/6 X BALB/c)F1 mice bearing palpable tumors (0.3-1.5 cm in diameter) were given an iv injection of 1 of 2 MoAb (one reactive and the other nonreactive) identically labeled with /sup 99m/TcNCl/sub 4//sup -/ and then scanned with a gamma camera, and/or the tissues were removed and the localization of /sup 99m/Tc-nitrido group-labeled MoAb was measured. Tumor localization of the reactive MoAb (1.8-2.2% of the injected dose) was four times greater than that of the nonreactive /sup 99m/TcN-MoAb (0.3-0.4% of the injected dose). The localization of specific /sup 99m/TcN-MoAb to a murine thymoma was observed in the gamma camera image at just 2 hours after injection. At 27 hours, tumors could readily be detected by /sup 99m/TcN-MoAb without the need for background subtraction. Nonreactive /sup 99m/TcN-MoAb did not image the tumors. The use of /sup 99m/TcN-MoAb offers substantial improvement over radioiodinated (/sup 125/I or /sup 131/I) MoAb for the detection of tumors. The use of /sup 99m/TcNCl/sub 4//sup -/ as a labeling agent results in /sup 99m/Tc-labeled MoAb with high specific activity and specificity when compared with the specific activity and specificity of the /sup 99m/Tc-MoAb prepared by using the conventional SnCl/sub 2/ reduction of pertechnetate.
- Research Organization:
- Univ. of Melbourne, Victoria, Australia
- OSTI ID:
- 5020160
- Journal Information:
- J. Natl. Cancer Inst.; (United States), Vol. 2
- Country of Publication:
- United States
- Language:
- English
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MONOCLONAL ANTIBODIES
DIAGNOSTIC USES
NEOPLASMS
DIAGNOSIS
SCINTISCANNING
MICE
TECHNETIUM 99
TISSUE DISTRIBUTION
ANIMALS
ANTIBODIES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
COUNTING TECHNIQUES
DIAGNOSTIC TECHNIQUES
DISEASES
DISTRIBUTION
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
RADIOISOTOPE SCANNING
RADIOISOTOPES
RODENTS
TECHNETIUM ISOTOPES
USES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
550601* - Medicine- Unsealed Radionuclides in Diagnostics