Discovery and functional characterization of canine PD-L1-targeted antibodies for evaluating antitumor efficacy in a canine osteosarcoma xenograft model

Sep 23, 2026

Uploaded by Levi

Targeting the PD-1/PD-L1 pathway is a promising cancer therapy strategy, yet no canine-specific PD-L1 antibodies have been approved. This study aimed to develop PD-L1-specific antibodies for canine cancer using phage display. A synthetic antibody library yielded 18 high-affinity scFv clones, converted to IgG to enhance binding and functional stability. Clone #15 showed the strongest binding and antitumor effects, inhibiting PD-1/PD-L1 interaction. Flow cytometry and thermal assays confirmed stability, and in NOG mice with canine osteosarcoma xenografts, antibody #15 reduced tumor size and weight while increasing apoptosis.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages11

Reading Time28 min

AccessFree to download

Background

PD-1/PD-L1 pathway in cancer therapy

Canine cancer burden and current treatments

Rationale for canine PD-L1 antibody development

Methods and Antibody Development

Phage display screening

Conversion from scFv to IgG format

Functional Characterization

Binding affinity and stability assays

PD-1/PD-L1 blockade

Antitumor Evaluation

Xenograft model and treatment outcomes

Effects on apoptosis and lymphocyte populations

[www. nature.com/scientificreports](www. nature.com/scientificreports) OPEN Discovery and functional characterization of canine PD-L1-targeted antibodies for evaluating antitumor efficacy in a canine osteosarcoma xenograft model Min-young Song1,4,6, Jaewon Cho1,6, Hyosung Park1, Yujeong Song1, Keon Kim2, Jae-Hee Ahn1, Chang-Min Lee2, Dae Hee Kim1,3,5􀀍 & Hyun-Jeong Ko1,3,4,5􀀍 Targeting the programmed cell death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) pathway is promising in treating cancer in humans and offers potential for veterinary applications. However, no PD-L1 antibodies have been approved specifically for treating canine cancer. We aimed to develop PDL1-specific antibodies using phage display technology for treating canine cancer. A synthetic antibody library was screened, and 18 high-affinity single-chain variable fragment clones were subsequently converted to the IgG format for enhancing binding affinity and functional stability. The clone \#15 exhibited the highest binding affinity and most pronounced antitumor effects. The PD-1/PD-L1 interaction was inhibited by antibody \#15. The binding and thermal stabilities of the antibodies were validated by flow cytometry and thermal stability assays, respectively. In NOG mice xenografted with canine osteosarcoma cells and treated with canine peripheral blood mononuclear cells and antibody \#15, the tumor size and weight were reduced. Antibody \#15 significantly increased apoptosis of tumor cells and lymphocyte populations. Therefore, anti-PD-L1 antibodies, particularly antibody \#15, have substantial potential as novel immunotherapeutic agents against canine osteosarcoma. This study represents a significant advancement in veterinary oncology, with the potential of improving treatment outcomes for canine cancers and providing insights into similar strategies in human cancer therapy. Keywords Canine cancer, Programmed death ligand 1, Immunotherapeutics, Antibody, Phage display Cancer is a prevalent health concern in dogs, exhibiting various types depending on factors such as breed and sex1–4. In canine oncology, the incidence of cancer exceeds four million new cases annually, thereby making it a leading cause of disease-related mortality in dogs5. Common tumors in dogs include lymphoma, osteosarcoma, mast cell tumors, nasal tumors, and mammary cancer6,7. The traditional therapies for canine cancer include surgery, radiotherapy, and chemotherapy. Recently, the demand for effective cancer treatments for pets has increased, prompting the exploration of immunotherapeutic approaches in veterinary medicine8. Monoclonal antibodies are significantly used as immunotherapeutic agents for treating human cancers9, 10. Monoclonal antibodies that specifically target immune checkpoint molecules and inhibit their signaling pathways have garnered significant attention, reflecting their potential in treating human cancers and promising potential use in canine cancers11, 12. In particular, monoclonal antibodies targeting the programmed cell death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) pathway have shown significant promise13, 14. PD-L1 possesses 1Department of Pharmacy, Kangwon National University, Chuncheon 24341, Republic of Korea. 2Department of Veterinary Internal Medicine, College of Veterinary Medicine and BK21 FOUR Program, Chonnam National University, Gwangju 61186, Republic of Korea. 3Kangwon Institute of Inclusive Technology, Kangwon National University, Chuncheon 24341, Republic of Korea. 4Innovative Drug Development Research Team for Intractable Diseases (BK21 Plus), Kangwon National University, Chuncheon 24341, Republic of Korea. 5Global/Gangwon Innovative Biologics-Regional Leading Research Center (GIB-RLRC), Kangwon National University, Chuncheon 24341, Republic of Korea. 6Min-young Song and Jaewon Cho have contributed equally to this work. 􀀍 email: [kimdh@kangwon.ac.kr](kimdh@kangwon.ac.kr); [hjko@kangwon.ac.kr](hjko@kangwon.ac.kr) [www. na

FAQs

What was the primary goal of the study?

To develop PD-L1-specific antibodies for canine cancer and evaluate their antitumor potential using phage display and downstream functional testing.

How were the antibodies generated and selected?

A synthetic antibody library was screened with phage display to obtain high-affinity scFv clones, which were then converted to an IgG format to improve binding affinity and functional stability.

Why was antibody #15 considered the best-performing clone?

It exhibited the highest binding affinity, strongly inhibited PD-1/PD-L1 interaction, and produced the most pronounced antitumor effects in the evaluated model.

Sep 23, 2026

Uploaded by Levi