Development of monoclonal antibody-linked ELISA for sero-diagnosis of vesicular stomatitis virus (VSV-IN) using baculovirus expressed glycoprotein.

This study focuses on the development of a monoclonal antibody-linked ELISA for diagnosing vesicular stomatitis virus in cattle and horses using a special glycoprotein. The researchers found that this method was relatively sensitive and specific in detection, suggesting that it could be applied for sero-diagnosis of this type of infection.

About Vesicular Stomatitis Virus and ELISA

• Vesicular Stomatitis Virus (VSV-IN) is a viral disease which primarily affects cattle and horses, leading to symptoms like vesicles, erosions, and sloughing of the skin on the muzzle, tongue, teats, and above the hooves.
• ELISA, or enzyme-linked immunosorbent assay, is a commonly used laboratory test to detect and measure antibodies in the blood. It has been widely used for disease diagnosis in both humans and animals.

Methodology of the Study

• The research team expressed the gene coding for the envelope glycoprotein (GP) of the VSV-IN under the polyhedron promoter of baculovirus.
• This recombinant GP was used as a diagnostic antigen to detect cattle and horse antibodies to VSV.
• The team then used a neutralizing monoclonal antibody (Mab) to GP of VSV-IN as a trapping antibody in one type of ELISA test and as a detecting antibody in another type of ELISA test.
• These ELISA tests were evaluated against the currently available C-ELISA tests from OIE reference laboratory for vesicular stomatitis.

Findings and Interpretation

• When tested on naturally infected equine sera (blood serum from horses) and bovine sera vaccinated against foot-and-mouth disease, the Mab-linked indirect ELISA (MLI-ELISA) and Mab-linked competitive ELISA (MLC-ELISA) showed sensitivities of 80% and 95% respectively, indicating the proportion of true positive results.
• The specificity of the tests, indicating the proportion of true negative results, was 97% and 99% respectively.
• The MLC-ELISA showed higher sensitivity and specificity, suggesting it to be a better test for sero-diagnosis of VSV-IN infections. However, both types of tests did cross-react with equine sera against the New Jersey VSV serotype, implying that the tests will also detect this serotype of the virus.

Conclusions

• According to the study, this new monoclonal antibody-linked ELISA, particularly the MLC-ELISA, could potentially be a more effective way of diagnosing Vesicular Stomatitis Virus in cattle and horses.
• However, the researchers acknowledge that the tests do have cross-reactivity with other serotypes and this is something that should be taken into consideration in further development of these diagnostic methods.