Identification of Two Novel Linear Neutralizing Epitopes within the Hexon Protein of Canine Adenovirus Using Monoclonal Antibodies
Shujie Wang,
Chunsheng Wang,
Xiao Ren,
Wenjiao Xue,
Haijuan He,
Yanzhu Zhu,
Hongfeng Wang,
Gang Wang,
Xuehui Cai
Affiliations
Shujie Wang
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
Chunsheng Wang
College of Life Science, Northeast Forestry University, Harbin 150040, China
Xiao Ren
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
Wenjiao Xue
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
Haijuan He
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
Yanzhu Zhu
Key Laboratory of Special Animal Epidemic Disease, Ministry of Agriculture, Institute of Special Animal and Plant Sciences, Chinese Academy of Agricultural Sciences, Changchun 130112, China
Hongfeng Wang
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
Gang Wang
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
Xuehui Cai
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
Canine adenovirus (CAdV) has a high prevalence in canine populations. High affinity neutralizing antibodies against conserved epitopes can provide protective immunity against CAdV and protect against future outbreaks. In this study, we identified two CAdV-2-specific neutralizing monoclonal antibodies (mAbs), 2C1 and 7D7, which recognized two linear-dependent epitopes. MAb 2C1 potently neutralized CAdV-2 with a 50% neutralization titer (NT50) of 4096, and mAb 7D7 partially neutralized CAdV-2 with a 50% NT50 of 64. Immunoprecipitation, Western blot and protein spectral analysis indicated that both neutralizing mAbs recognized the hexon protein (Hex) of CAdV-2. Through a 12-mer random peptide phage display and synthetic peptides analysis, we finely mapped the neutralizing epitopes to two 10-amino acid (aa) peptides within the CAdV Hex: 634RIKQRETPAL643 located on the surface region; and 736PESYKDRMYS745 located in the inner region of the expected 3D structure of trimeric Hex. Importantly, the two epitopes are highly conserved among all CAdV isolates by sequence alignment analysis. Thus, these results provide insights into the interaction between virus and mAbs at the aa level and may have potential applications in the development of novel therapeutic or epitope-based vaccines, antibody therapeutics and a diagnostic method suitable for the rapid detection of all CAdVs.
