Detection of antibodies to equine arteritis virus by a monoclonal antibody-based blocking ELISA.

The research article is about the development of an Enzyme-Linked Immunosorbent Assay (ELISA) to detect antibodies against the equine arteritis virus in horses, that provides accurate results in a shorter timeframe and at a lower cost than existing methods.

Study Methodology

• The research began by preparing a potent ELISA antigen from the equine arteritis virus (EAV), a disease affecting horses. This was done by carrying out a process known as differential centrifugation of EAV-infected cell culture fluid. The resulting material was then treated with a compound called Triton X-100 for solubilization.
• The team used this potent ELISA antigen and a mouse-generated monoclonal antibody that targets G(L), a protein of EAV, to develop a blocking ELISA (bELISA) – a laboratory method used for the detection of EAV antibodies in horse blood samples.

Testing and Results

• The bELISA was evaluated using a total of 837 serum samples. The sensitivity (ability to correctly identify those with the disease) of the bELISA as compared to the traditional serum neutralization (SN) test was 99.4%, indicating a high level of reliability.
• The study also found that bELISA is a highly specific (ability to correctly identify those without the disease) test, and its accuracy was not negatively affected by previous exposures of the horses to non-EAV-containing substances.
• Out of 119 certain serum samples, 21 came from horses with no past exposure to EAV, and 98 originated from thoroughbred racehorses. All but one of these samples tested negative for EAV antibodies with both the SN test and bELISA. One sample was SN-negative but showed a suspicious reaction in the bELISA.
• When considering a larger sample set of 517 SN-negative samples from both the field and experimental horses, excluding any suspicious results, the relative specificity of the bELISA was found to be 97.7%.

Conclusion

• The study suggests that samples should be examined both in their undiluted form and in a 1/10 dilution while employing bELISA. This is crucial as the testing of sera with high neutralizing antibody titers may be influenced by a prozone-like phenomenon (a false negative result).
• Lastly, the study concludes that bELISA represents a faster and more cost-efficient test than the SN test for the detection of EAV antibodies in equine serum samples. This could potentially lead to more widespread testing and early detection of the disease, improving the overall health and wellbeing of horses.