Epitope Identification and Application for Diagnosis of Duck Tembusu Virus Infections in Ducks.
Duck Tembusu virus (DTMUV) causes substantial egg drop disease. DTMUV was first identified in China and rapidly spread to Malaysia and Thailand. The antigenicity of the DTMUV E protein has not yet been characterized. Here, we investigated antigenic sites on the E protein using the non-neutralizing monoclonal antibodies (mAbs) 1F3 and 1A5. Two minimal epitopes were mapped to221LD/NLPW225and87YAEYI91by using phage display and mutagenesis. DTMUV-positive duck sera reacted with the epitopes, thus indicating the importance of the minimal amino acids of the epitopes for antibody-epitope binding. The performance of the dot blotting assay with the corresponding positive sera indicated that YAEYI was DTMUV type-specific, whereas221LD/NLPW225was a cross-reactive epitope for West Nile virus (WNV), dengue virus (DENV), and Japanese encephalitis virus (JEV) and corresponded to conserved and variable amino acid sequences among these strains. The structure model of the E protein revealed that YAEYI and LD/NLPW were located on domain (D) II, which confirmed that DII might contain a type-specific non-neutralizing epitope. The YAEYI epitope-based antigen demonstrated its diagnostic potential by reacting with high specificity to serum samples obtained from DTMUV-infected ducks. Based on these observations, a YAEYI-based serological test could be used for DTMUV surveillance and could differentiate DTMUV infections from JEV or WNV infections. These findings provide new insights into the organization of epitopes on flavivirus E proteins that might be valuable for the development of epitope-based serological diagnostic tests for DTMUV.
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China. lichenxihsy@126.com.
Chenxi
C
Li
School of Electrical Engineering & Automation, Harbin Institute of Technology, Harbin 150006, China. junyanliu@126.com.
Junyan
J
Liu
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China. luke0871@aliyun.com.
Wulin
W
Shaozhou
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China. baixiaofei_1@163.com.
Xiaofei
X
Bai
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China. zhangqingshan91@126.com.
Qingshan
Q
Zhang
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China. huaronghong@163.com.
Ronghong
R
Hua
Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung 402, Taiwan. jhliu@nchu.edu.tw.
Jyung-Hurng
JH
Liu
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China. liuming04@126.com.
Ming
M
Liu
State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China. yunzhang03@yahoo.com.
Yun
Y
Zhang
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D000956:Antigens, Viral / Q000276:immunology; D001715:Bird Diseases / Q000175:diagnosis* / Q000821:virology*; D002681:China; D018604:Epitope Mapping; D000939:Epitopes / Q000276:immunology*; D005416:Flavivirus / Q000276:immunology*; D018177:Flavivirus Infections / Q000175:diagnosis / Q000662:veterinary*; D008296:Malaysia; D012698:Serologic Tests / Q000379:methods*; D013785:Thailand
D000914:Antibodies, Viral; D000956:Antigens, Viral; D000939:Epitopes
E protein 3D structure; E protein epitopes; diagnosis; duck Tembusu virus; type specific and cross-reactive epitopes