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Home / Equine Research Bank / Can J Vet Res / Evidence that antibodies against recombinant SnSAG1 of Sarco...
Canadian journal of veterinary research = Revue canadienne de recherche veterinaire2009; 73(3); 176-183;

Evidence that antibodies against recombinant SnSAG1 of Sarcocystis neurona merozoites are involved in infection and immunity in equine protozoal myeloencephalitis.

Abstract: Sarcocystis neurona is the principal etiologic agent of equine protozoal myeloencephalitis (EPM). An immunodominant protein of S. neurona, SnSAG-1, is expressed by the majority of S. neurona merozoites isolated from spinal tissues of horses diagnosed with EPM and may be a candidate for diagnostic tests and prophylaxis for EPM. Five horses were vaccinated with adjuvanted recombinant SnSAG1 (rSnSAG1) and 5 control (sham vaccinated) horses were vaccinated with adjuvant only. Serum was evaluated pre- and post-vaccination, prior to challenge, for antibodies against rSnSAG1 and inhibitory effects on the infectivity of S. neurona by an in vitro serum neutralization assay. The effect of vaccination with rSnSAG1 on in vivo infection by S. neurona was evaluated by challenging all the horses with S. neurona merozoites. Blinded daily examinations and 4 blinded neurological examinations were used to evaluate the presence of clinical signs of EPM. The 5 vaccinated horses developed serum and cerebrospinal fluid (CSF) titers of SnSAG1, detected by enzyme-linked immunosorbent assay (ELISA), post-vaccination. Post-vaccination serum from vaccinated horses was found to have an inhibitory effect on merozoites, demonstrated by in vitro bioassay. Following the challenge, the 5 control horses displayed clinical signs of EPM, including ataxia. While 4 of the 5 vaccinated horses did not become ataxic. One rSnSAG-1 vaccinated horse showed paresis in 1 limb with muscle atrophy. All horses showed mild, transient, cranial nerve deficits; however, disease did not progress to ataxia in rSnSAG-1 vaccinated horses. The study showed that vaccination with rSnSAG-1 produced antibodies in horses that neutralized merozoites when tested by in vitro culture and significantly reduced clinical signs demonstrated by in vivo challenge. est le principal agent étiologique de l’encéphalomyélite équine à protozoaire (EPM). Une protéine immunodominante de SnSAG-1, est exprimée par la majorité des mérozoïtes de isolés de tissus de la moelle épinière de chevaux avec un diagnostic d’EPM et pourrait être un candidat pour des tests diagnostiques et la prophylaxie de l’EPM. Cinq chevaux ont été vaccinés avec une protéine SnSAG1 recombinante avec adjuvant (rSnSAG1) et 5 chevaux témoins (faux vaccinés) ont été vaccinés avec de l’adjuvant seulement. Des échantillons de sérum prélevés pré-et post-vaccination, avant l’infection, ont été testés pour la présence d’anticorps dirigés contre rSnSAG1 et les effets inhibiteurs sur l’infectivité de S. par une épreuve in vitro de séro-neutralisation. Les effets de la vaccination avec rSNsAG1 sur l’infection in vivo par ont été examinés en infectant tous les chevaux avec des mérozoïtes de . Des examens quotidiens à l’aveugle et 4 examens neurologiques à l’aveugle ont été effectués pour évaluer la présence de signes cliniques d’EPM. Les 5 chevaux vaccinés ont développé des anticorps sériques et dans le liquide céphalo-rachidien (CSF) post-vaccination contre SnSAG1, détectés par essai immuno-enzymatique (ELISA). Le sérum post-vaccination provenant des chevaux vaccinés avait un effet inhibiteur sur les mérozoïtes tel que démontré par un bio-essai in vitro. Suite à l’infection, les 5 chevaux témoins ont montré des signes cliniques d’EPM, incluant de l’ataxie. Quatre des 5 chevaux vaccinés ne sont pas devenus ataxiques. Un des chevaux vaccinés avec rSnSAG-1 a montré de la parésie à un membre avec atrophie musculaire. Tous les chevaux ont montré des déficits légers et transitoires des nerfs crâniens; toutefois, la condition n’a pas progressé jusqu’à l’ataxie chez les chevaux vaccinés avec rSnSAG-1. Cette étude a démontré que la vaccination des chevaux avec rSnSAG-1 a induit des anticorps qui neutralisaient les mérozoïtes lorsque testés par culture in vitro et a réduit de manière significative les signes cliniques tel que démontré par une infection défi in vivo. (Traduit par Docteur Serge Messier)
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Publication Date: 2009-10-02 PubMed ID: 19794889PubMed Central: PMC2705071
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  • 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.

This research is about the potential use of SnSAG1, a protein from the organism, Sarcocystis neurona, which causes equine protozoal myeloencephalitis (EPM), in diagnostic tests and vaccines. Through experimentation involving vaccination, serological tests, and challenge trials, the study shows that a vaccine containing SnSAG1 can produce antibodies that neutralize the disease-causing agent and significantly reduce clinical signs in horses.

Research Scope and Methodology

  • The research focused mainly on Sarcocystis neurona, the primary cause of EPM, a devastating neurological disease in horses.
  • The scientists explored the potential use of recombinant SnSAG1 (rSnSAG1), an immunodominant protein expressed by S. neurona.
  • Five horses were vaccinated with rSnSAG1, and five controls were vaccinated with an adjuvant only. Serum was evaluated pre- and post-vaccination for antibodies against rSnSAG1 and their inhibition effect on the infectivity of S. neurona.
  • All the horses were then challenged with S. neurona merozoites to assess the effect of rSnSAG1 vaccination on in vivo infection. Daily and neurological examinations were performed to evaluate signs of EPM.

Findings and Significance

  • The five horses that receive the vaccine composed of rSnSAG1 developed serum and cerebrospinal fluid (CSF) titers of SnSAG1 after vaccination as depicted by ELISA tests.
  • Post-vaccination serum from the vaccinated horses was found to inhibit merozoites as demonstrated by an in vitro bioassay.
  • Following the challenge with S. neurona merozoites, the control horses exhibited signs of EPM, including a condition caused ataxia. However, four out of five vaccinated horses did not become ataxic, indicating an immunity buildup due to the vaccine.
  • The study therefore concluded that the vaccine with rSnSAG1 brings about the production of antibodies in horses that neutralize the merozoites when tested in vitro and significantly reduce clinical signs when challenged in vivo.
  • This research hence holds potential for developing effective diagnostic tests and prevention strategies for EPM, a debilitating disease in horses with currently limited treatment options.

Cite This Article

APA
Ellison S, Witonsky S. (2009). Evidence that antibodies against recombinant SnSAG1 of Sarcocystis neurona merozoites are involved in infection and immunity in equine protozoal myeloencephalitis. Can J Vet Res, 73(3), 176-183.

Publication

Canadian journal of veterinary research = Revue canadienne de recherche veterinaire
ISSN: 1928-9022
NlmUniqueID: 8607793
Country: Canada
Language: English
Volume: 73
Issue: 3
Pages: 176-183

Researcher Affiliations

Ellison, Siobhan
  • Pathogenes Inc, Fairfield, FL 32634, USA. sellison@pathogenes.com
Witonsky, Sharon

    MeSH Terms

    • Animals
    • Antibodies, Protozoan / blood
    • Antibodies, Protozoan / cerebrospinal fluid
    • Antigens, Protozoan / pharmacology
    • Encephalomyelitis / immunology
    • Encephalomyelitis / parasitology
    • Encephalomyelitis / prevention & control
    • Encephalomyelitis / veterinary
    • Female
    • Horse Diseases / immunology
    • Horse Diseases / parasitology
    • Horse Diseases / prevention & control
    • Horses
    • Male
    • Neutralization Tests / veterinary
    • Protozoan Proteins / pharmacology
    • Recombinant Proteins / pharmacology
    • Sarcocystis / immunology
    • Sarcocystosis / immunology
    • Sarcocystosis / parasitology
    • Sarcocystosis / prevention & control
    • Sarcocystosis / veterinary
    • Single-Blind Method
    • Vaccination / veterinary

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    Citations

    This article has been cited 1 times.
    1. Dubey JP, Howe DK, Furr M, Saville WJ, Marsh AE, Reed SM, Grigg ME. An update on Sarcocystis neurona infections in animals and equine protozoal myeloencephalitis (EPM). Vet Parasitol 2015 Apr 15;209(1-2):1-42.
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