It is challenging to treat canine brucellosis due to the immune evading and stealthy characteristic of the causative bacteria, Brucella (B.) canis. Gold nanoparticle aptamer (AuNP-Apt) conjugated antimicrobial peptide (AMP) is a promising alternative to antibiotics for various bacterial infections. However, the toxicity of AuNP-Apt has been variable throughout research, and the in vivo toxic mechanism has not been fully elucidated. This study evaluated the therapeutic potential against B. canis, and the toxicity of AuNP-Apt conjugated antimicrobial peptide, RW-BP100 (AuNP-AptHis-RW-BP100His), in a mouse model. Intravenous (IV) treatment with AuNP-AptHis-RW-BP100His reduced the bacteria burden and histopathologic lesions. The IV treatment also induced CD4+ T cell differentiation and modulated serum cytokine levels. However, high-dose AuNP-Apt was lethal, resulting in tissue accumulation and vessel embolism. Therefore, AuNP-AptHis-RW-BP100His is a promising therapeutic agent for B. canis treatment, but due to its toxicity, further studies are needed for its utilization in clinical practice.

Abstract
INTRODUCTION
MATERIALS AND METHODS
    Gold nanoparticle conjugated peptide preparation
    Bacterial strain and growth condition
    Mice infection and treatment
    CD4+ and CD8+ T-cell differentiation
    Serum cytokine analysis
    Histological assessment
    Statistical analysis
RESULTS
    Therapeutic potential of AuNP-AptHis-RW-BP100Hison B. canis infected ICR mice
Effect of AuNP-AptHis-RW-BP100His on host immuneresponse in ICR mice
Toxicity of AuNP-AptHis-RW-BP100His on B. canisinfected ICR mice
DISCUSSION
ACKNOWLEDGEMENTS
CONFLICT OF INTEREST
REFERENCES

• Seong Eun Cho(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju, 52828, Korea)
• Trang Thi Nguyen(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju, 52828, Korea)
• Ched Nicole Turbela Aguilar(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju, 52828, Korea)
• Eoin Quiatchon Lajara(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju, 52828, Korea)
• Il-Hwa Hong(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju, 52828, Korea)
• Won-Gi Min(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju, 52828, Korea)
• Hu-Jang Lee(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju, 52828, Korea)
• Suk Kim(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju, 52828, Korea) Corresponding author
• Tran Xuan Ngoc Huy(Institute of Applied Sciences, HUTECH University, 475A Dien Bien Phu St., Ward 25, Binh Thanh District, Ho Chi Minh City, Viet Nam)
• Ji-Hyun Yeom(Department of Life Science, Chung-Ang University, Seoul, 06974, Korea)