Suppressive effect of staphylococcal enterotoxin B on murine contact hypersensitivity

Superantigens (SAg) possess the capacity to interact with particular V beta regions of T cell receptor (TCR) and major histocompatibility complex (MHC) class II molecules, and activate a large number of T cells and accessory cells. staphylococcal enterotoxins (SEs) are recently well known as SAg and anticipate to modulate immunological reactions. In this study, we investigated the effect of staphylococcal enterotoxin B (SEB) on contact hypersensitivity reaction (CHR) to 2,4-dinitrofluorobenzene (DNFB) in BALB/c mice. SEB-injection inhibited the induction of sensitization on CHR. Suppressor cells were not found in the spleen or lymph node cells from mice treated with SEB. Normal spleen cells cultured with SEB showed significant proliferation and tumor necrosis factor-alpha (TNF-alpha) production. CHR was suppressed by intravenous injection of the culture supernatant. In addition, anti-TNF-alpha antibodies inhibited the suppressive effect induced by the supernatant. These findings indicate that TNF-alpha produced by SEB-responding cells inhibits the induction of sensitization on CHR. Therefore, SAg may play important roles in the modulation of immune system through the stimulation of TNF-alpha production.