Patterns of Interferon-γ mRNA Expression in Toxic Shock Syndrome Toxin-1 Expanded Vβ11+ T Lymphocytes

We have recently demonstrated that toxic shock syndrome toxin-1 (TSST-1), a staphylococcal exotoxin with superantigenic properties, is involved in the pathogenesis of septic arthritis. The aim of the current study was to characterize in detail the in vitro properties of TSST-1 with regard to T cell activation patterns. We demonstrate that TSST-1 preferentially expands murine Vβ11+ T lymphocytes and this expansion occurs equally well within CD4 and CD8 compartments. To analyze the functional properties of Vβ11+ T cells expanded in response to TSST-1, we have utilized a combined in situ hybridization and immunocytochemistry method. With this technique we show that TSST-1-stimulated Vβ+ T cells are an important source of IFNγ mRNA synthesis, suggesting that this cytokine may participate in superantigen-mediated septic arthritis.