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Home / Equine Research Bank / Infect Immun / Contribution of each of four Superantigens to Streptococcus ...
Infection and immunity2010; 78(4); 1728-1739; doi: 10.1128/IAI.01079-09

Contribution of each of four Superantigens to Streptococcus equi-induced mitogenicity, gamma interferon synthesis, and immunity.

Abstract: Streptococcus equi is the causative agent of strangles, the most frequently diagnosed infectious disease of horses worldwide. The disease is characterized by abscessation and swelling of the lymph nodes of the head and neck, which can literally strangle the horse to death. S. equi produces four recently acquired phage-associated bacterial superantigens (sAgs; SeeH, SeeI, SeeL, and SeeM) that share homology with the mitogenic toxins of Streptococcus pyogenes. The aim of this study was to characterize the contribution of each of these S. equi sAgs to mitogenic activity in vitro and quantify the sAg-neutralizing capacity of sera from naturally infected horses in order to better understand their role in pathogenicity. Each of the sAgs was successfully cloned, and soluble proteins were produced in Escherichia coli. SeeI, SeeL, and SeeM induced a dose-dependent proliferative response in equine CD4 T lymphocytes and synthesis of gamma interferon (IFN-gamma). SeeH did not stimulate equine peripheral blood mononuclear cells (PBMC) but induced proliferation of asinine PBMC. Allelic replacement mutants of S. equi strain 4047 with sequential deletion of the superantigen genes were generated. Deletion of seeI, seeL, and seeM completely abrogated the mitogenic activity and synthesis of IFN-gamma, in equine PBMC, of the strain 4047 culture supernatant. Sera from naturally infected convalescent horses had only limited sAg-neutralizing activities. We propose that S. equi sAgs play an important role in S. equi pathogenicity by stimulating an overzealous and inappropriate Th1 response that may interfere with the development of an effective immune response.
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Publication Date: 2010-02-01 PubMed ID: 20123710PubMed Central: PMC2849420DOI: 10.1128/IAI.01079-09Google Scholar: Lookup
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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 study explored the role of four different superantigens produced by the bacteria called Streptococcus equi, which causes a common and severe horse disease known as strangles. The research revealed how each superantigen contributes to the disease’s development and the immune response it triggers in horses.

About Streptococcus equi and Strangles

  • Streptococcus equi is responsible for strangles, a highly infectious disease that primarily affects horses.
  • Strangles is characterized by swelling and formation of abscesses in the lymph nodes of the horse’s head and neck, which could potentially strangle the horse to death.
  • The bacteria produce four superantigens, termed SeeH, SeeI, SeeL, and SeeM. These superantigens are similar to the toxins produced by another bacteria, Streptococcus pyogenes.

Research Aim and Methodology

  • The research aimed to understand each superantigen’s role in disease development and the immune response it triggers.
  • Scientists cloned each of the superantigens and produced them as soluble proteins in the bacterium Escherichia coli for their experiments.

Findings of the Study

  • Three superantigens, SeeI, SeeL, and SeeM, were found to induce a dose-dependent increase in the proliferation of CD4 T lymphocytes, a type of white blood cell, in horses, along with the synthesis of an immune-response protein called gamma interferon.
  • However, the SeeH superantigen did not show any significant stimulatory impact on horse white blood cells but was active in asinine (donkey family) white blood cells.
  • When these superantigen genes were deleted from the bacterial strain, it resulted in loss of disease-causing ability and synthesis of gamma interferon, confirming the role of these superantigens in the disease development.
  • Blood serum from horses that had recovered from the infection demonstrated only limited potential to neutralize these superantigens.

Conclusions of the Study

  • The study concluded that the superantigens produced by Streptococcus equi play a critical role in pathogenicity by triggering an aggressive and inappropriate immune response.
  • This excessive immune response could be interfering with the development of an effective immune response and thus be a key factor in the severity and progression of the disease.

Cite This Article

APA
Paillot R, Robinson C, Steward K, Wright N, Jourdan T, Butcher N, Heather Z, Waller AS. (2010). Contribution of each of four Superantigens to Streptococcus equi-induced mitogenicity, gamma interferon synthesis, and immunity. Infect Immun, 78(4), 1728-1739. https://doi.org/10.1128/IAI.01079-09

Publication

Infection and immunity
ISSN: 1098-5522
NlmUniqueID: 0246127
Country: United States
Language: English
Volume: 78
Issue: 4
Pages: 1728-1739

Researcher Affiliations

Paillot, Romain
  • Animal Health Trust, Centre for Preventive Medicine, Lanwades Park, Newmarket, Suffolk CB8 7UU, United Kingdom. romain.paillot@aht.org.uk
Robinson, Carl
    Steward, Karen
      Wright, Nicola
        Jourdan, Thibaud
          Butcher, Nicola
            Heather, Zoe
              Waller, Andrew S

                MeSH Terms

                • Animals
                • Antibodies, Bacterial / blood
                • Antibodies, Neutralizing / blood
                • Antigens, Bacterial / genetics
                • Antigens, Bacterial / immunology
                • Cell Proliferation
                • Cells, Cultured
                • Gene Knockout Techniques
                • Horses
                • Interferon-gamma / biosynthesis
                • Leukocytes, Mononuclear / immunology
                • Streptococcus equi / immunology
                • Superantigens / genetics
                • Superantigens / immunology

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                This article has been cited 18 times.
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