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Published on: June 14, 2024
Generation and in vivo characterization of a chimeric αvβ5-targeting antibody 14C5 and its derivatives
Caroline Dumolyn1, Steve Schoonooghe, Lieselotte Moerman
1Laboratory of Radiopharmacy, University of Ghent, Harelbekestraat 72, Ghent, 9000, Belgium. Caroline.Dumolyn@UGent.be.
Background:
Previous studies showed that radiolabeled murine monoclonal antibody (mAb) 14C5 and its Fab and F(ab')2 fragments, targeting αvβ5 integrin, have promising properties for diagnostic and therapeutic applications in cancer. To diminish the risk of generating a human anti-mouse antibody response in patients, chimeric variants were created. The purpose of this study was to recombinantly produce chimeric antibody (chAb) derivatives of the murine mAb 14C5 and to evaluate the in vitro and in vivo characteristics.
Methods:
In vitro stability, specificity, and affinity of radioiodinated chAb and fragments (Iodo-Gen method) were examined on high-expressing αvβ5 A549 lung tumor cells. In vivo biodistribution and pharmacokinetic characteristics were studied in A549 lung tumor-bearing Swiss Nu/Nu mice.
Results:
Saturation binding experiments revealed high in vitro affinity of radioiodinated chAb, F(ab')2, and Fab, with dissociation constants (KD) of 1.19 ± 0.19, 0.68 ± 0.10, and 2.11 ± 0.58 nM, respectively. ChAb 14C5 showed highest tumor uptake (approximately 10%ID/g) at 24 h post injection, corresponding with other high-affinity Abs. ChF(ab')2 and chFab fragments showed faster clearance from the blood compared to the intact Ab.
Conclusions:
The chimerization of mAb 14C5 and its fragments has no or negligible effect on the properties of the antibody. In vitro and in vivo properties show that the chAb 14C5 is promising for radioimmunotherapy, due to its high maximum tumor uptake and its long retention in the tumor. The chF(ab')2 fragment shows a similar receptor affinity and a faster blood clearance, causing less non-specific retention than the chAb. Due to their fast blood clearance, the fragments show high potential for radioimmunodiagnosis.
Insights
Chimeric antibody 14C5 and its fragments targeting αvβ5 integrin show promising properties for cancer radioimmunotherapy and radioimmunodiagnosis. Chimeric antibody 14C5 demonstrates high tumor uptake and retention, while fragments offer faster blood clearance for improved imaging.
Area of Science:
- Oncology
- Immunology
- Radiochemistry
Background:
- Murine monoclonal antibody (mAb) 14C5 and its fragments target αvβ5 integrin, showing potential in cancer diagnostics and therapeutics.
- Chimeric variants were developed to reduce the human anti-mouse antibody response.
- Previous studies indicated promising properties for mAb 14C5 and its fragments in cancer applications.
Purpose of the Study:
- To recombinantly produce chimeric antibody (chAb) derivatives of murine mAb 14C5.
- To evaluate the in vitro and in vivo characteristics of these chimerized antibodies and fragments.
Main Methods:
- In vitro assessment of radioiodinated chAb and fragments' stability, specificity, and affinity using A549 lung tumor cells.
- In vivo biodistribution and pharmacokinetic studies in A549 lung tumor-bearing Swiss Nu/Nu mice.
- Radioiodination was performed using the Iodo-Gen method.
Main Results:
- High in vitro affinity was observed for radioiodinated chAb, F(ab')2, and Fab fragments (KD values ranging from 0.68 to 2.11 nM).
- Chimeric antibody 14C5 exhibited the highest tumor uptake (approximately 10%ID/g at 24 h post-injection).
- Chimeric fragments (chF(ab')2 and chFab) demonstrated faster blood clearance compared to the intact chimeric antibody.
Conclusions:
- Chimerization of mAb 14C5 and its fragments minimally impacts their properties.
- ChAb 14C5 is a promising candidate for radioimmunotherapy due to high tumor uptake and retention.
- Chimeric fragments show potential for radioimmunodiagnosis owing to similar receptor affinity and faster blood clearance, reducing non-specific retention.
