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Monoclonal antibodies for specific cell labeling: considerations, preparations and preliminary evaluation
International Journal of Radiation Applications and Instrumentation. Part B, Nuclear Medicine and Biology
|January 1, 1987
Summary
Researchers developed radiolabeled monoclonal antibodies (MAbs) for platelet imaging. These agents show specific binding to platelets and hold promise for visualizing experimental thrombi in vivo.
Area of Science:
- Biomedical Imaging
- Immunology
- Radiochemistry
Background:
- Monoclonal antibodies (MAbs) offer specific targeting for diagnostic applications.
- Platelet glycoprotein IIIa is a key target for antibody-based therapies and imaging.
Purpose of the Study:
- To evaluate two types of radiolabeled monoclonal antibodies (MAbs) as agents for labeling platelets.
- To assess the binding characteristics and in vivo imaging potential of these labeled MAbs.
Main Methods:
- Two MAbs, B79.7 and B59.2, specific for human platelet glycoprotein IIIa, were labeled with 125I and 111In using DTPA bifunctional chelation.
- Scatchard analysis was performed to determine binding affinities (Kd) and the number of binding sites on human platelets.
- The imaging capability of 111In-DTPA-B59.2 labeled platelets was assessed by imaging experimental thrombi in vivo.
Main Results:
- Both radiolabeled MAbs demonstrated saturable binding to human platelets.
- Kd values for 111In-B79.7 and 125I-B79.7 were in the nanomolar range (83.3 x 10^-9 M and 113.3 x 10^-9 M, respectively).
- In vivo imaging showed promising thrombi-to-blood ratios (15.8 at 2 hours post-injection).
Conclusions:
- Radiolabeled MAbs, specifically 111In-DTPA-B59.2, can effectively label platelets for imaging purposes.
- These agents show potential for visualizing experimental thrombi and warrant further investigation.