Evaluation of new leptospiral antigens for the diagnosis of equine leptospirosis: An approach using pan-genomic analysis, reverse vaccinology and antigenic selection.
Abstract: The current gold standard diagnostic test for leptospirosis is the microscopic agglutination test (MAT), which has many drawbacks; therefore, the development of a better and easier serological test for leptospirosis is needed. Objective: To apply reverse vaccinology (RV) and antigenic selection on the assortment of leptospiral targets and evaluate their potential for use as reagents for the diagnosis of equine leptospirosis. Methods: Cross-sectional study. Methods: The antigenic selection parameters were: proteins with antigenicity score ≥0.5 (VaxiJen), at least one B cell epitope and size between 10 and 275 KDa. New leptospiral proteins were cloned, expressed and serologically screened against equine sera (n = 128) on a single analysis and comparative combinations. Sensitivity (Se) and specificity (Sp), accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated. A BLAST with nucleotide and protein sequences was used to identify the serovar or species specificity. Conclusions: This cross-sectional analysis had three main limitations: (a) The equine sera used in these tests were limited to sera submitted to the Animal Health Diagnosis Center and were only tested against seven serovars; (b) MAT results were considered being 'perfect', and the highest titre presented was considered being the infecting serovar, which may not hold true; (c) The strains used to represent the serovars and the limited number of different serovars and species included in the genetic analysis, which leads to the possibility that these proteins might be present in different species or serovars that perhaps would be seroprevalent in another geographic region. Conclusions: The new leptospiral antigens described in this research could increase the sensitivity and specificity of ELISA for detection of Leptospira exposure and the detection of leptospirosis in horses along with support from other clinical signs. Some of these new antigens might be used to improve the detection of infecting serovar.
© 2020 EVJ Ltd.
Publication Date: 2020-12-03 PubMed ID: 33135163DOI: 10.1111/evj.13380Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The researchers in this article aim to find new leptospiral antigens capable of enhancing the process of diagnosing equine leptospirosis, a disease in horses resulting from leptospiral bacteria. They use a variety of methods, including reverse vaccinology, to predict and select the best antigens that can make tests more accurate and efficient compared to the current diagnostic method, the microscopic agglutination test (MAT).
Methods
- The researchers use a variety of methods such as reverse vaccinology (RV) and antigenic selection to predict and select the best leptospiral targets that can be used to improve the process of diagnosing equine leptospirosis.
- They run an antigenic selection based on parameters such as proteins with an antigenicity score equal to or greater than 0.5, at least one B cell epitope, and protein size between 10 and 275 KDa.
- The researchers clone and express new leptospiral proteins, and they screen these against horse sera on a single analysis and comparative combinations.
- They calculate the sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of these potential new diagnostic reagents.
Limitations
- The researchers acknowledge several limitations in their study. These include (a) limitations with the horse sera used in the tests; (b) overreliance on MAT results, and (c) limitations with the serovar and species strains used in the analysis.
- Among these limitations, the researchers mention that the horse sera used in the tests were limited to those submitted to the Animal Health Diagnosis Center, and these were only tested against seven serovars.
- They also admit that the highest titre MAT results were considered to be the infecting serovar, which may not always be the case.
- Finally, they mention the limitations related to the representation of the serovars and the limited variety of serovars and species included in the genetic analysis.
Conclusion
- The researchers suggest that the new leptospiral antigens identified through their research could enhance the sensitivity and specificity of ELISA for detecting leptospirosis in horses.
- They propose that these new antigens could support the detection of leptospirosis in horses, particularly when used in combination with clinical signs.
- According to the researchers, some of these antigens might be used to enhance the detection of the infecting serovar, thus contributing to improved diagnosis of equine leptospirosis.
Cite This Article
APA
Zilch TJ, Lee JJ, Bressan GC, McDonough SP, Mohammed HO, Divers TJ, Chang YF.
(2020).
Evaluation of new leptospiral antigens for the diagnosis of equine leptospirosis: An approach using pan-genomic analysis, reverse vaccinology and antigenic selection.
Equine Vet J, 53(5), 1025-1035.
https://doi.org/10.1111/evj.13380 Publication
Researcher Affiliations
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.
- Department of Biochemistry and Molecular Biology, Federal University of Viçosa, Viçosa, MG, Brazil.
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA.
MeSH Terms
- Agglutination Tests / veterinary
- Animals
- Antibodies, Bacterial
- Antigens, Bacterial
- Cross-Sectional Studies
- Genomics
- Horse Diseases / diagnosis
- Horses
- Leptospira / genetics
- Leptospirosis / diagnosis
- Leptospirosis / veterinary
- Vaccinology
References
This article includes 55 references
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
