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Volume 49, Number 2, April 2016

Development of a multiplex Luminex assay for detecting swine antibodies to structural and nonstructural proteins of foot-and-mouth disease virus in Taiwan 


Tsu-Han Chen, Fan Lee, Yeou-Liang Lin, Chu-Hsiang Pan, Chia-Ni Shih, Chun-Hsien Tseng, Hsiang-Jung Tsai


 

Corresponding author:

Correspondence
Corresponding author. Hsiang-Jung Tsai, School of Veterinary Medicine, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan. 



 

Background and purpose: 

Foot-and-mouth disease (FMD) and swine vesicular disease (SVD) are serious vesicular diseases that have devastated swine populations throughout the world. The aim of this study was to develop a multianalyte profiling (xMAP) Luminex assay for the differential detection of antibodies to the FMD virus of structural proteins (SP) and nonstructural proteins (NSP). 



 

Methods:

After the xMAP was optimized, it detected antibodies to SP-VP1 and NSP-3ABC of the FMD virus in a single serum sample. These tests were also compared with 3ABC polypeptide blocking enzyme-linked immunosorbent assay (ELISA) and virus neutralization test (VNT) methods for the differential diagnosis and assessment of immune status, respectively. 



 

Results:

To detect SP antibodies in 661 sera from infected naïve pigs and vaccinated pigs, the diagnostic sensitivity (DSn) and diagnostic specificity (DSp) of the xMAP were 90.0–98.7% and 93.0–96.5%, respectively. To detect NSP antibodies, the DSn was 90% and the DSp ranged from 93.3% to 99.1%. The xMAP can detect the immune response to SP and NSP as early as 4 days postinfection and 8 days postinfection, respectively. Furthermore, the SP and NSP antibodies in all 15 vaccinated but unprotected pigs were detected by xMAP. A comparison of SP and NSP antibodies detected in the sera of the infected samples indicated that the results from the xMAP had a high positive correlation with results from the VNT and a 3ABC polypeptide blocking ELISA assay. However, simultaneous quantitation detected that xMAP had no relationship with the VNT. Furthermore, the specificity was 93.3–94.9% with 3ABC polypeptide blocking ELISA for the FMDV-NSP antibody.
 



 

Conclusion:

The results indicated that xMAP has the potential to detect antibodies to FMDV-SP-VP1 and NSP-3ABC and to distinguish FMDV-infected pigs from pigs infected with the swine vesicular disease virus. 



 

Key words:

antibody detection, foot-and-mouth disease virus, multiplex Luminex assay, nonstructural protein, structural protein