Canine CD117-Specific Antibodies with Diverse Binding Properties Isolated from a Phage Display Library Using...

Area of Science:

• Veterinary Medicine
• Molecular Biology
• Immunology

Background:

• Canine CD117 (c-Kit) is a tyrosine kinase receptor frequently overexpressed in canine tumors.
• The juxtamembrane domain of canine CD117 shares 100% homology with humans, making it a significant target for cancer therapy and comparative oncology.
• Existing monoclonal antibodies (mAbs) lack specificity for canine CD117, necessitating the development of targeted therapies.

Purpose of the Study:

• To isolate and characterize novel monoclonal antibodies (mAbs) specifically targeting canine CD117 (c-Kit).
• To evaluate the binding affinity and specificity of these mAbs against canine CD117 for potential therapeutic applications in canine cancers.

Main Methods:

• A naive phage display library was panned using recombinant canine CD117 expressed on whole cells.
• Isolated mAbs were characterized for binding affinity to recombinant and native canine CD117 using various assays.
• Competitive binding assays were performed using stem cell factor (SCF) to assess antibody interaction with the CD117 receptor.

Main Results:

• Several mAbs demonstrated low- to sub-nanomolar binding affinity for recombinant canine CD117.
• Immunohistochemistry and flow cytometry confirmed antibody binding to native canine CD117.
• Competitive assays indicated that some isolated mAbs bind to the CD117 receptor, potentially interfering with stem cell factor (SCF) binding.

Conclusions:

• The cell-based biopanning strategy successfully identified a panel of mAbs with diverse binding characteristics.
• The developed mAbs show potential as therapeutic candidates for targeting CD117-overexpressing canine cancers.
• These findings support the utility of these novel mAbs in veterinary oncology and comparative cancer research.