Staphylococcal superantigens in colonization and disease

Stacey X Xu,John K Mccormick

doi:10.3389/fcimb.2012.00052

Abstract

Superantigens (SAgs) are a family of potent immunostimulatory exotoxins known to be produced by only a few bacterial pathogens, including Staphylococcus aureus. More than 20 distinct SAgs have been characterized from different S. aureus strains and at least 80% of clinical strains harbor at least one SAg gene, although most strains encode many. SAgs have been classically associated with food poisoning and toxic shock syndrome (TSS), for which these toxins are the causative agent. TSS is a potentially fatal disease whereby SAg-mediated activation of T cells results in overproduction of cytokines and results in systemic inflammation and shock. Numerous studies have also shown a possible role for SAgs in other diseases such as Kawasaki disease (KD), atopic dermatitis (AD), and chronic rhinosinusitis (CRS). There is also now a rich understanding of the mechanisms of action of SAgs, as well as their structures and function. However, we have yet to discover what purpose SAgs play in the life cycle of S. aureus, and why such a wide array of these toxins exists. This review will focus on recent developments within the SAg field in terms of the molecular biology of these toxins and their role in both colonization and disease.

Highlights

Bacterial superantigens (SAgs) represent a unique class of exotoxins which all function to activate enormous numbers of T lymphocytes (McCormick et al, 2001; Llewelyn and Cohen, 2002; Proft and Fraser, 2003)
Given the wide variety and high prevalence of SAg genes, it is likely that these genes would be lost, especially since they are primarily encoded on mobile genetic elements, without a contribution to the fitness of S. aureus
Re-stimulation of peripheral blood mononuclear cells (PBMCs) taken during the acute phase of disease with exogenous SAg resulted in proliferation of Vβ2+ cells suggesting that T cells were not rendered anergic (Rasigade et al, 2011)

Summary

Staphylococcal superantigens in colonization and disease

Reviewed by: Thomas Proft, University of Auckland, New Zealand Victor J. Superantigens (SAgs) are a family of potent immunostimulatory exotoxins known to be produced by only a few bacterial pathogens, including Staphylococcus aureus. SAgs have been classically associated with food poisoning and toxic shock syndrome (TSS), for which these toxins are the causative agent. TSS is a potentially fatal disease whereby SAg-mediated activation of T cells results in overproduction of cytokines and results in systemic inflammation and shock. We have yet to discover what purpose SAgs play in the life cycle of S. aureus, and why such a wide array of these toxins exists. This review will focus on recent developments within the SAg field in terms of the molecular biology of these toxins and their role in both colonization and disease

INTRODUCTION

Xu and McCormick

STAPHYLOCOCCAL SUPERANTIGENS AND THEIR HOST RECEPTORS

Findings

STAPHYLOCOCCAL SUPERANTIGENS AND DISEASE