Abstract | UNLABELLED: METHODS: F(ab')(2) and Fab 14C5 fragments were radioiodinated using the Iodo-Gen method. In vitro stability, binding specificity and affinity of (125)I-labeled 14C5 fragments were studied in A549 lung carcinoma cells. Biodistribution, blood clearance and tumor-targeting characteristics of (131)I-labeled 14C5 fragments and intact mAb 14C5 were studied in Swiss nu/nu mice bearing A549 lung carcinoma tumors. Planar gamma imaging illustrated the potential use of these (123)I-labeled 14C5 fragments for radioimmunodetection (RID). RESULTS: Saturation binding experiments showed highest affinity for (125)I-labeled F(ab')(2) fragments (K(d)=0.37+/-0.10 nmol/L) and lowest affinity for (125)I-labeled Fab fragments (K(d)=2.25+/-0.44 nmol/L). Blood clearance studies showed that the alpha half-life (t(1/2)alpha) value for Fab, F(ab')(2) and mAb 14C5 was 14.9, 21 and 118 min, respectively. The beta half-life t(1/2)beta value for Fab, F(ab')(2) and mAb 14C5 was 439, 627 and 4067 min, respectively. (131)I-Fab fragments showed highest tumor uptake 3 h after injection (2.4+/-0.8 %ID/g), (131)I-labeled F(ab')(2) showed highest tumor uptake 6 h after injection (4.7+/-0.7 %ID/g) and for (131)I-labeled mAb highest tumor uptake was observed at 24 h (10.7+/-2.3 %ID/g). In planar gamma imaging, both labeled fragments gave better tumor-to-background contrast than (123)I-mAb 14C5. CONCLUSION:
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Authors | Ingrid J G Burvenich, Steve Schoonooghe, Peter Blanckaert, Klaus Bacher, Liesbet Vervoort, Elisabeth Coene, Nico Mertens, Filip De Vos, Guido Slegers |
Journal | Nuclear medicine and biology
(Nucl Med Biol)
Vol. 34
Issue 3
Pg. 257-65
(Apr 2007)
ISSN: 0969-8051 [Print] United States |
PMID | 17383575
(Publication Type: Journal Article)
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Chemical References |
- 14C5 monoclonal antibody
- Antibodies, Monoclonal
- Immunoglobulin Fab Fragments
- Iodine Radioisotopes
- Radiopharmaceuticals
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Topics |
- Animals
- Antibodies, Monoclonal
(pharmacokinetics)
- Cell Line, Tumor
- Immunoglobulin Fab Fragments
(metabolism)
- Iodine Radioisotopes
(pharmacokinetics)
- Lung Neoplasms
(diagnostic imaging, metabolism)
- Metabolic Clearance Rate
- Mice
- Mice, Nude
- Organ Specificity
- Radionuclide Imaging
(methods)
- Radiopharmaceuticals
(pharmacokinetics)
- Tissue Distribution
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