Induction of selective anergy by toxic shock syndrome toxin-1 in CD8+ T cells

Interferon-gamma (IFN-gamma) mRNA expression of murine splenic CD8+ T cells in response to toxic shock syndrome toxin-1 (TSST-1) was examined in vitro. In primary response to TSST-1, purified CD8+ cells expressed a low frequency of IFN-gamma mRNA and produced very little interleukin-2 (IL-2) compared with unseparated lymphocytes and purified CD4+ cells. The addition of IL-2 to the cell culture enhanced IFN-gamma mRNA expression in the CD8+ population. Upon restimulation with TSST-1, no IL-2 production and hardly any IFN-gamma mRNA expression were observed in the purified CD8+ lymphoblasts. Exogenously added IL-2 did not increase the IFN-gamma mRNA expression in purified CD8+ blasts exposed to TSST-1. In contrast, stimulation with concanavalin A induced a high frequency of IFN-gamma mRNA in purified CD8+ blasts. Moreover, TSST-1 induced strong IFN-gamma mRNA expression in unseparated T lymphoblasts and purified CD4+ populations. Interestingly, a combined immunocytochemistry and in situ hybridization technique showed a high frequency of CD8+ IFN-gamma mRNA-expressing cells in an unseparated blast population. These results demonstrate that TSST-1 induces a selective anergy within the purified CD8- T-cell compartment and that the IFN-gamma mRNA expression in CD8+ T blasts can be achieved by stimulation of unseparated T cells with TSST-1.