FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
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)
Get Full Text
Publication Date: 2009-10-02 PubMed ID: 19794889PubMed Central: PMC2705071
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.
LinkedInCopy
  • 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

    References

    This article includes 30 references
    1. Beech J, Dodd DC. Toxoplasma-like encephalomyelitis in the horse.. Vet Pathol 1974;11(1):87-96.
      pubmed: 4215208doi: 10.1177/030098587401100110google scholar: lookup
    2. Boy MG, Galligan DT, Divers TJ. Protozoal encephalomyelitis in horses: 82 cases (1972-1986).. J Am Vet Med Assoc 1990 Feb 15;196(4):632-4.
      pubmed: 2303389
    3. Dubey JP, Davis GW, Koestner A, Kiryu K. Equine encephalomyelitis due to a protozoan parasite resembling Toxoplasma gondii.. J Am Vet Med Assoc 1974 Aug 1;165(3):249-55.
      pubmed: 4845678
    4. Dubey JP, Davis SW, Speer CA, Bowman DD, de Lahunta A, Granstrom DE, Topper MJ, Hamir AN, Cummings JF, Suter MM. Sarcocystis neurona n. sp. (Protozoa: Apicomplexa), the etiologic agent of equine protozoal myeloencephalitis.. J Parasitol 1991 Apr;77(2):212-8.
      pubmed: 1901359
    5. Cheadle MA, Lindsay DS, Rowe S, Dykstra CC, Williams MA, Spencer JA, Toivio-Kinnucan MA, Lenz SD, Newton JC, Rolsma MD, Blagburn BL. Prevalence of antibodies to Neospora sp. in horses from Alabama and characterisation of an isolate recovered from a naturally infected horse [corrected].. Int J Parasitol 1999 Oct;29(10):1537-43.
      pubmed: 10608440doi: 10.1016/s0020-7519(99)00140-xgoogle scholar: lookup
    6. Hoane JS, Gennari SM, Dubey JP, Ribeiro MG, Borges AS, Yai LE, Aguiar DM, Cavalcante GT, Bonesi GL, Howe DK. Prevalence of Sarcocystis neurona and Neospora spp. infection in horses from Brazil based on presence of serum antibodies to parasite surface antigen.. Vet Parasitol 2006 Mar 15;136(2):155-9.
      pubmed: 16310955doi: 10.1016/j.vetpar.2005.10.023google scholar: lookup
    7. Fenger CK, Granstrom DE, Langemeier JL, Stamper S, Donahue JM, Patterson JS, Gajadhar AA, Marteniuk JV, Xiaomin Z, Dubey JP. Identification of opossums (Didelphis virginiana) as the putative definitive host of Sarcocystis neurona.. J Parasitol 1995 Dec;81(6):916-9.
      pubmed: 8544064
    8. Dubey JP, Davis SW, Speer CA, Bowman DD, de Lahunta A, Granstrom DE, Topper MJ, Hamir AN, Cummings JF, Suter MM. Sarcocystis neurona n. sp. (Protozoa: Apicomplexa), the etiologic agent of equine protozoal myeloencephalitis.. J Parasitol 1991 Apr;77(2):212-8.
      pubmed: 1901359
    9. Bowman DD, Cummings JF, Davis SW, deLahunta A, Dubey JP, Suter MM, Rowland PH, Conner DL. Characterization of Sarcocystis neurona from a thoroughbred with equine protozoal myeloencephalitis.. Cornell Vet 1992 Jan;82(1):41-52.
      pubmed: 1740059
    10. Ellison SP, Greiner E, Brown K, Kennedy T. Experimental infection of horses with S. neurona merozoites as a model for Equine Protozoal Myeloencephalitis. J App Res Vet Med 2004;2:79–89.
    11. Granstrom DE, Alvarez O Jr, Dubey JP, Comer PF, Williams NM. Equine protozoal myelitis in Panamanian horses and isolation of Sarcocystis neurona.. J Parasitol 1992 Oct;78(5):909-12.
      pubmed: 1403437
    12. Marsh AE, Johnson PJ, Ramos-Vara J, Johnson GC. Characterization of a Sarcocystis neurona isolate from a Missouri horse with equine protozoal myeloencephalitis.. Vet Parasitol 2001 Feb 26;95(2-4):143-54.
      pubmed: 11223195doi: 10.1016/s0304-4017(00)00386-1google scholar: lookup
    13. Saville WJ, Stich RW, Reed SM, Njoku CJ, Oglesbee MJ, Wunschmann A, Grover DL, Larew-Naugle AL, Stanek JF, Granstrom DE, Dubey JP. Utilization of stress in the development of an equine model for equine protozoal myeloencephalitis.. Vet Parasitol 2001 Feb 26;95(2-4):211-22.
      pubmed: 11223201doi: 10.1016/s0304-4017(00)00421-0google scholar: lookup
    14. Sofaly CD, Reed SM, Gordon JC, Dubey JP, Ogleebee MJ, Njoku CJ, Grover DL, Saville WJ. Experimental induction of equine protozoan myeloencephalitis (EPM) in the horse: effect of Sarcocystis neurona sporocyst inoculation dose on the development of clinical neurologic disease.. J Parasitol 2002 Dec;88(6):1164-70.
      pubmed: 12537112doi: 10.1645/0022-3395(2002)088[1164:eioepm]2.0.co;2google scholar: lookup
    15. Saville WJ, Sofaly CD, Reed SM, Dubey JP, Oglesbee MJ, Lacombe VA, Keene RO, Gugisberg KM, Swensen SW, Shipley RD, Chiang YW, Chu HJ, Ng T. An equine protozoal myeloencephalitis challenge model testing a second transport after inoculation with Sarcocystis neurona sporocysts.. J Parasitol 2004 Dec;90(6):1406-10.
      pubmed: 15715237doi: 10.1645/ge-128rgoogle scholar: lookup
    16. Heskett KA, Mackay RJ. Antibody index and specific antibody quotient in horses after intragastric administration of Sarcocystis neurona sporocysts.. Am J Vet Res 2008 Mar;69(3):403-9.
      pubmed: 18312140doi: 10.2460/ajvr.69.3.403google scholar: lookup
    17. Liang FT, Granstrom DE, Zhao XM, Timoney JF. Evidence that surface proteins Sn14 and Sn16 of Sarcocystis neurona merozoites are involved in infection and immunity.. Infect Immun 1998 May;66(5):1834-8.
      pmc: PMC108132pubmed: 9573058doi: 10.1128/iai.66.5.1834-1838.1998google scholar: lookup
    18. Ellison SP, Omara-Opyene AL, Yowell CA, Marsh AE, Dame JB. Molecular characterisation of a major 29 kDa surface antigen of Sarcocystis neurona.. Int J Parasitol 2002 Feb;32(2):217-25.
      pubmed: 11812499doi: 10.1016/s0020-7519(01)00324-1google scholar: lookup
    19. Ellison SP, Kennedy T, Brown K. Development of an ELISA to detect antibodies to rSNSAG1 in the horse. J App Res Vet Med 2003;1(4):318–327.
    20. Sellon DC, Knowles DP, Greiner EC, Long MT, Hines MT, Hochstatter T, Tibary A, Dame JB. Infection of immunodeficient horses with Sarcocystis neurona does not result in neurologic disease.. Clin Diagn Lab Immunol 2004 Nov;11(6):1134-9.
      pmc: PMC524751pubmed: 15539518doi: 10.1128/cdli.11.6.1134-1139.2004google scholar: lookup
    21. Long MT, Mines MT, Knowles DP, Tanhauser SM, Dame JB, Cutler TJ, MacKay RJ, Sellon DC. Sarcocystis neurona: parasitemia in a severe combined immunodeficient (SCID) horse fed sporocysts.. Exp Parasitol 2002 Mar;100(3):150-4.
      pubmed: 12173399doi: 10.1016/s0014-4894(02)00012-7google scholar: lookup
    22. Ellison SP, Kennedy T, Brown K. Early signs of equine protozoal myeloencephalitis. J App Res Vet Med 2003;1(4):272–278.
    23. Casadevall A, Pirofski LA. A reappraisal of humoral immunity based on mechanisms of antibody-mediated protection against intracellular pathogens.. Adv Immunol 2006;91:1-44.
      pubmed: 16938537doi: 10.1016/s0065-2776(06)91001-3google scholar: lookup
    24. Fayer R, Dubey JP. Protective immunity against clinical sarcocystosis in cattle.. Vet Parasitol 1984 Sep;15(3-4):187-201.
      pubmed: 6437053doi: 10.1016/0304-4017(84)90071-2google scholar: lookup
    25. Lindsay DS, Thomas NJ, Dubey JP. Biological characterisation of Sarcocystis neurona isolated from a Southern sea otter (Enhydra lutris nereis).. Int J Parasitol 2000 Apr 24;30(5):617-24.
      pubmed: 10779575doi: 10.1016/s0020-7519(00)00034-5google scholar: lookup
    26. Lindsay DS, Dubey JP, Horton KM, Bowman DD. Development of Sarcocystis falcatula in cell cultures demonstrates that it is different from Sarcocystis neurona.. Parasitology 1999 Mar;118 ( Pt 3):227-33.
      pubmed: 10205798doi: 10.1017/s003118209800376xgoogle scholar: lookup
    27. Dubey JP, Mattson DE, Speer CA, Hamir AN, Lindsay DS, Rosenthal BM, Kwok OC, Baker RJ, Mulrooney DM, Tornquist SJ, Gerros TC. Characteristics of a recent isolate of Sarcocystis neurona (SN7) from a horse and loss of pathogenicity of isolates SN6 and SN7 by passages in cell culture.. Vet Parasitol 2001 Feb 26;95(2-4):155-66.
      pubmed: 11223196doi: 10.1016/s0304-4017(00)00387-3google scholar: lookup
    28. Dubey JP, Mattson DE, Speer CA, Baker RJ, Mulrooney DM, Tornquist SJ, Hamir AN, Gerros TC. Characterization of a Sarcocystis neurona isolate (SN6) from a naturally infected horse from Oregon.. J Eukaryot Microbiol 1999 Sep-Oct;46(5):500-6.
      pubmed: 10519218doi: 10.1111/j.1550-7408.1999.tb06067.xgoogle scholar: lookup
    29. Howe DK, Gaji RY, Marsh AE, Patil BA, Saville WJ, Lindsay DS, Dubey JP, Granstrom DE. Strains of Sarcocystis neurona exhibit differences in their surface antigens, including the absence of the major surface antigen SnSAG1.. Int J Parasitol 2008 May;38(6):623-31.
      pubmed: 17980881doi: 10.1016/j.ijpara.2007.09.007google scholar: lookup
    30. Hyun C, Gupta GD, Marsh AE. Sequence comparison of Sarcocystis neurona surface antigen from multiple isolates.. Vet Parasitol 2003 Feb 28;112(1-2):11-20.
      pubmed: 12581581doi: 10.1016/s0304-4017(02)00392-8google scholar: lookup

    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.
      doi: 10.1016/j.vetpar.2015.01.026pubmed: 25737052google scholar: lookup
    Subscribe to our newsletter
    Join 99,780 horse owners like you who receive our email updates on horse health and nutrition.