A new trivalent SnSAG surface antigen chimera for efficient detection of antibodies against Sarcocystis neurona and diagnosis of equine protozoal myeloencephalitis.
Abstract: Enzyme-linked immunosorbent assays (ELISAs) based on the SnSAG surface antigens of Sarcocystis neurona provide reliable detection of infection by the parasite. Moreover, accurate serodiagnosis of equine protozoal myeloencephalitis (EPM) is achieved with the SnSAG ELISAs by measuring antibodies in serum and cerebrospinal fluid (CSF) to reveal active infection in the central nervous system. Two independent ELISAs based on recombinant (r)SnSAG2 or a chimeric fusion of SnSAG3 and SnSAG4 (rSnSAG4/3) are currently used together for EPM serodiagnosis to overcome varied antibody responses in different horses. To achieve reliable antibody detection with a single ELISA instead of 2 separate ELISAs, rSnSAG2 was fused with rSnSAG4/3 into a single trivalent protein, designated rSnSAG2/4/3. Paired serum and CSF from 163 horses were tested with all 3 ELISAs. When the consensus antibody titers obtained with the rSnSAG2 and rSnSAG4/3 ELISAs were compared to the single SAG2/4/3 ELISA titers, Spearman rank correlation coefficients of ρ = 0.74 and ρ = 0.90 were obtained for serum and CSF, respectively, indicating strong agreement between the tests. When the rSnSAG2 and rSnSAG4/3 consensus serum-to-CSF titer ratio was compared to the rSnSAG2/4/3 serum-to-CSF titer ratio, the Spearman correlation coefficient was ρ = 0.87, again signifying strong agreement. Importantly, comparing the diagnostic interpretation of the serum-to-CSF titer ratios yielded a Cohen kappa value of 0.77. These findings suggest that the single ELISA based on the trivalent rSnSAG2/4/3 will provide serologic and diagnostic results that are highly comparable to the consensus of the 2 independent ELISAs based on rSnSAG2 and rSnSAG4/3.
© 2015 The Author(s).
Publication Date: 2015-05-05 PubMed ID: 25943129DOI: 10.1177/1040638715584995Google Scholar: Lookup
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- Evaluation Study
- Journal Article
- Research Support
- Non-U.S. Gov't
- Antibodies
- Cerebrospinal Fluid
- Clinical Study
- Diagnosis
- Diagnostic Technique
- Disease
- Disease Diagnosis
- Enzyme-Linked Immunosorbent Assay (ELISA)
- Equine Health
- Equine Protozoal Myeloencephalitis
- Horses
- Immunology
- Infection
- Infectious Disease
- Laboratory Methods
- Protozoa
- Sarcocystis
- Serodiagnosis
- Serum
- Veterinary Care
- Veterinary Medicine
Summary
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This study presents a trivalent SnSAG surface antigen chimera that allows for efficient detection of antibodies against Sarcocystis neurona, a parasite causing equine protozoal myeloencephalitis (EPM) in horses. The new method combines two existing detection assays into a single test, yielding results that are highly comparable to the two separate assays.
Background of the Study
- The study was motivated by the need to simplify the process of detecting Sarcocystis neurona, a protozoan that causes equine protozoal myeloencephalitis (EPM), a debilitating neurological disease in horses.
- Previously, two independent Enzyme-linked immunosorbent assays (ELISAs) were used concurrently for diagnosis. This process was cumbersome, hence the need for a singular, more efficient assay.
Creation of the Trivalent SnSAG Antigen Chimera
- The researchers created a trivalent antigen chimera by fusing rSnSAG2 with rSnSAG4/3, creating a single protein known as rSnSAG2/4/3.
- These are recombinant surface antigens from the Sarcocystis neurona parasite, which when presented to the immune system elicit an antibody response.
Testing and Analysis of the New ELISA
- The trivalent SnSAG chirmera was then tested on 163 horses.
- The new rSnSAG2/4/3 ELISA was compared with the consensus titers of the original separate rSnSAG2 and rSnSAG4/3 ELISAs.
- Statistical analyses including Spearman rank correlation and the Cohen kappa value were performed to evaluate the efficacy of the new ELISA. The results indicated a strong agreement between the tests, proving the reliability and efficiency of the new trivalent antigen chimera.
Significance of the Findings
- The study found that the trivalent rSnSAG2/4/3 ELISA provides highly comparable results to the two separate ELISAs. This means that a single test can be utilised, making diagnosis quicker and more efficient.
- The creation of rSnSAG2/4/3 streamlines the detection process of Sarcocystis neurona and thus facilitates the diagnosis and subsequent treatment of equine protozoal myeloencephalitis (EPM).
Cite This Article
APA
Yeargan M, de Assis Rocha I, Morrow J, Graves A, Reed SM, Howe DK.
(2015).
A new trivalent SnSAG surface antigen chimera for efficient detection of antibodies against Sarcocystis neurona and diagnosis of equine protozoal myeloencephalitis.
J Vet Diagn Invest, 27(3), 377-381.
https://doi.org/10.1177/1040638715584995 Publication
Researcher Affiliations
- Department of Veterinary Science, University of Kentucky, Lexington, KY (Yeargan, Rocha, Reed, Howe)Rood and Riddle Equine Hospital, Lexington, KY (Reed)Equine Diagnostic Solutions LLC, Lexington, KY (Morrow, Graves).
- Department of Veterinary Science, University of Kentucky, Lexington, KY (Yeargan, Rocha, Reed, Howe)Rood and Riddle Equine Hospital, Lexington, KY (Reed)Equine Diagnostic Solutions LLC, Lexington, KY (Morrow, Graves).
- Department of Veterinary Science, University of Kentucky, Lexington, KY (Yeargan, Rocha, Reed, Howe)Rood and Riddle Equine Hospital, Lexington, KY (Reed)Equine Diagnostic Solutions LLC, Lexington, KY (Morrow, Graves).
- Department of Veterinary Science, University of Kentucky, Lexington, KY (Yeargan, Rocha, Reed, Howe)Rood and Riddle Equine Hospital, Lexington, KY (Reed)Equine Diagnostic Solutions LLC, Lexington, KY (Morrow, Graves).
- Department of Veterinary Science, University of Kentucky, Lexington, KY (Yeargan, Rocha, Reed, Howe)Rood and Riddle Equine Hospital, Lexington, KY (Reed)Equine Diagnostic Solutions LLC, Lexington, KY (Morrow, Graves).
- Department of Veterinary Science, University of Kentucky, Lexington, KY (Yeargan, Rocha, Reed, Howe)Rood and Riddle Equine Hospital, Lexington, KY (Reed)Equine Diagnostic Solutions LLC, Lexington, KY (Morrow, Graves) dkhowe2@uky.edu.
MeSH Terms
- Animals
- Antibodies, Protozoan / blood
- Antibodies, Protozoan / immunology
- Antigens, Protozoan / immunology
- Antigens, Surface / immunology
- Chimera
- Encephalomyelitis / diagnosis
- Encephalomyelitis / parasitology
- Encephalomyelitis / veterinary
- Enzyme-Linked Immunosorbent Assay / veterinary
- Horse Diseases / diagnosis
- Horses
- Protozoan Proteins / immunology
- Sarcocystis / immunology
- Sarcocystis / isolation & purification
- Sarcocystosis / diagnosis
- Sarcocystosis / parasitology
- Sarcocystosis / veterinary
Citations
This article has been cited 4 times.- Sánchez-Ovejero C, Akdur E, Manzano-Román R, Hernández-González A, González-Sánchez M, Becerro-Recio D, González-Miguel J, Akhan O, Cretu CM, Vutova K, Tamarozzi F, Mariconti M, Brunetti E, Vola A, Fabiani M, Casulli A, Siles-Lucas M. Evaluation of the sensitivity and specificity of GST-tagged recombinant antigens 2B2t, Ag5t and DIPOL in ELISA for the diagnosis and follow up of patients with cystic echinococcosis. PLoS Negl Trop Dis 2020 Nov;14(11):e0008892.
- Alvarado-Esquivel C, Howe DK, Yeargan MR, Alvarado-Esquivel D, Alfredo Zamarripa-Barboza J, Dubey JP. Seroepidemiology of Sarcocystis neurona and Neospora hughesi infections in domestic donkeys (Equus asinus) in Durango, Mexico. Parasite 2017;24:27.
- Gutiérrez-Expósito D, García-Bocanegra I, Howe DK, Arenas-Montes A, Yeargan MR, Ness SL, Ortega-Mora LM, Álvarez-García G. A serosurvey of selected cystogenic coccidia in Spanish equids: first detection of anti-Besnoitia spp. specific antibodies in Europe. BMC Vet Res 2017 May 10;13(1):128.
- Ojo KK, Dangoudoubiyam S, Verma SK, Scheele S, DeRocher AE, Yeargan M, Choi R, Smith TR, Rivas KL, Hulverson MA, Barrett LK, Fan E, Maly DJ, Parsons M, Dubey JP, Howe DK, Van Voorhis WC. Selective inhibition of Sarcocystis neurona calcium-dependent protein kinase 1 for equine protozoal myeloencephalitis therapy. Int J Parasitol 2016 Dec;46(13-14):871-880.
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