New ELISA Test Improves Control of Duck Plague

CHINA - A new ELISA test based on thymidine kinase protein offers potential for the better detection of duck plague virus, say researchers at Sichuan Agricultural University.

27 April 2010

3 minute read

Asia

Y. Wen and colleagues at Sichuan Agricultural University have published a paper in Virology Journal on their work with a thymidine kinase recombinant protein-based ELISA for detecting antibodies to Duck Plague Virus (DPV).

They explain that DPV is the causative agent of duck plague (DP), which causes significant morbidity and mortality throughout duck-producing areas of the world. The diagnosis of DP currently relies on the use of live or inactivated whole DPV virion as antigens in ELISA, but it is too laborious and expensive for routine application, and it is still difficult to get purified DPV virion with current technology.

Results

In this study, Wen and co-authors describe the expression and purification of a recombinant thymidine kinase (TK) protein, which makes antigen in an in-house developed, optimised and standardised ELISA. The specificity of the optimised TK-ELISA was evaluated by antisera against DPV, Duck Hepatitis B Virus (DHBV), Duck Hepatitis Virus (DHV), Riemerella anatipestifer (RA), Escherichia coli (E. coli) and Salmonella anatum (S. anatum).

Only antisera against DPV yielded a specific and strong signal.

In order to determine the sensitivity of the TK-ELISA, a panel of diluted sera was tested, and the minimum detection limit of 1:2560 (OD450nm=0.401) was obtained according to the end-point cut-off (0.2438).

The repeatability and reproducibility under the experimental conditions demonstrates a low variability (P>0.05).

The suspected sera samples (n=30) were determined by TK-ELISA and the positive rate is 90 per cent (27/30), and the TK-ELISA showed 83.33 per cent (22+3/30) coincidence rate with the Serum Neutralization Test (SNT) and 90 per cent (24+3/30) coincidence rate with the whole DPV virion based-ELISA (DPV-ELISA).

When defining the dynamics of antibody response to attenuated live DPV vaccine, the maximum antibodies is reached after four weeks.

Conclusions

Wen and co-authors say that their results suggest that the TK-ELISA provides high specificity, sensitivity, repeatability and reproducibility for detection of anti-DPV antibodies in duck sera, and has the potential to be much simpler than DPV-ELISA and SNT for the sera epidemiological investigation.

Reference

Wen Y., A. Cheng, M. Wang, H. Ge, C. Shen, S. Liu, J. Xiang, R. Jia, D. Zhu, X. Chen, B. Lian, H. Chang and Y. Zhou. 2010. A thymidine kinase recombinant protein-based ELISA for detecting antibodies to Duck Plague Virus. Virology Journal, 7:77. doi:10.1186/1743-422X-7-77.