Induction of cytokines in human whole blood cultures by a mitogen derived from Mycoplasma arthritidis and by staphylococcal enterotoxin B.

Mycoplasma arthritidis produces a so-far only partially characterized soluble material (MAS) that has a potent mitogenic effect on T lymphocytes of several species. Similar to staphylococcal enterotoxins and a number of related toxins secreted by other species of bacteria, nanogram quantities of these so-called superantigens are sufficient to induce significant amounts of cytokines in the supernatant of lymphocyte cultures. Induction of interleukin-6 (IL-6) by MAS in murine bone marrow-derived macrophages has recently been described. In our study, we examined the differential effects of MAS and Staphylococcus aureus enterotoxin B (SEB) on human blood cells. When compared to MAS, SEB induced a higher proliferative response and, accordingly, a higher release of IFN-gamma. In contrast, large amounts of the macrophage products IL-1, IL-6 and tumor necrosis factor alpha (TNF-alpha) were observed in supernatants of cell cultures stimulated with MAS, whereas only small amounts were induced by SEB. Staphylococci and mycoplasmas are responsible for a number of diseases with various symptoms in man and animals. Our results suggest that SEB and MAS show different qualities in lymphocyte and macrophage stimulation which may be relevant in the pathogenesis of diseases.