Differential inhibitory effects of interleukin-10, interleukin-4, and dexamethasone on staphylococcal enterotoxin-induced cytokine production and T cell activation.

The cytokine profile of human peripheral blood mononuclear cells (PBMC) stimulated by staphylococcal enterotoxin (SE) A and B was examined. Production of tumor necrosis factor (TNF alpha), interleukin (IL)-1, IL-6, IL-2, and gamma interferon (IFN-gamma) was observed. In contrast, Th2 cytokines IL-4 and IL-10 were absent from SEA- or SEB-stimulated PBMC. Moreover, adding IL-10 to SE-stimulated PBMC inhibited the production of IL-1, IL-6, TNF alpha, and IFN gamma by 50 to 80% but had less effect (8-30%) on T cell proliferation. IL-4 was less effective than IL-10 in inhibiting cytokine production and enhanced T cell proliferation by SEA or SEB. The anti-inflammatory agent, dexamethasone, was the most potent agent in controlling the SE-mediated effects as evidenced by inhibited T cell proliferation (55%) and reduced levels of IL-1, IL-6, and IFN gamma (60% to 100%) and TNF alpha (50%). Reducing levels of toxic mediators such as TNF alpha, IL-1, IL-6, and IFN gamma by dexamethasone in SE-induced T cell responses may be a useful therapeutic strategy to circumvent SE toxicity and pathogenesis.