Systemic inflammatory response elicited by superantigen destabilizes T regulatory cells, rendering them ineffective during toxic shock syndrome

Ashenafi Y. Tilahun, Vaidehi R. Chowdhary, Chella S. David, Govindarajan Rajagopalan

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Life-threatening infections caused by Staphylococcus aureus, particularly the community-acquired methicillin-resistant strains of S. aureus, continue to pose serious problems. Greater virulence and increased pathogenicity of certain S. aureus strains are attributed to higher prevalence of exotoxins. Of these exotoxins, the superantigens (SAg) are likely most pathogenic because of their ability to rapidly and robustly activate the T cells even in extremely small quantities. Therefore, countering SAg-mediated T cell activation using T regulatory cells (Tregs) might be beneficial in diseases such as toxic shock syndrome (TSS). As the normal numbers of endogenous Tregs in a typical host are insufficient, we hypothesized that increasing the Treg numbers by administration of IL-2/anti-IL-2 Ab immune complexes (IL2C) or by adoptive transfer of ex vivo expanded Tregs might be more effective in countering SAg-mediated immune activation. HLA-DR3 transgenic mice that closely recapitulate human TSS were treated with IL2C to increase endogenous Tregs or received ex vivo expanded Tregs. Subsequently, they were challenged with SAg to induce TSS. Analyses of various parameters reflective of TSS (serum cytokine/chemokine levels, multiple organ pathology, and SAg-induced peripheral T cell expansion) indicated that increasing the Tregs failed to mitigate TSS. On the contrary, serum IFN-γ levels were increased in IL2C-treated mice. Exploration into the reasons behind the lack of protective effect of Tregs revealed IL-17 and IFN-γ-dependent loss of Tregs during TSS. In addition, significant upregulation of glucocorticoid-induced TNFR family-related receptor on conventional T cells during TSS could render them resistant to Treg-mediated suppression, contributing to failure of Treg-mediated immune regulation.

Original languageEnglish (US)
Pages (from-to)2919-2930
Number of pages12
JournalJournal of immunology (Baltimore, Md. : 1950)
Volume193
Issue number6
DOIs
StatePublished - Sep 15 2014

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Superantigens
Regulatory T-Lymphocytes
Septic Shock
Interleukin-2
Antigen-Antibody Complex
T-Lymphocytes
Exotoxins
Virulence
Staphylococcus aureus
HLA-DR3 Antigen
Interleukin-17
Adoptive Transfer
Methicillin-Resistant Staphylococcus aureus
Serum
Chemokines
Transgenic Mice
Glucocorticoids
Up-Regulation
Pathology
Cytokines

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Systemic inflammatory response elicited by superantigen destabilizes T regulatory cells, rendering them ineffective during toxic shock syndrome. / Tilahun, Ashenafi Y.; Chowdhary, Vaidehi R.; David, Chella S.; Rajagopalan, Govindarajan.

In: Journal of immunology (Baltimore, Md. : 1950), Vol. 193, No. 6, 15.09.2014, p. 2919-2930.

Research output: Contribution to journalArticle

Tilahun, Ashenafi Y. ; Chowdhary, Vaidehi R. ; David, Chella S. ; Rajagopalan, Govindarajan. / Systemic inflammatory response elicited by superantigen destabilizes T regulatory cells, rendering them ineffective during toxic shock syndrome. In: Journal of immunology (Baltimore, Md. : 1950). 2014 ; Vol. 193, No. 6. pp. 2919-2930.
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