SEB superantigen induces steroid resistance in PBMCs / 中国病理生理杂志

ABSTRACT

AIM: To establish a model of staphylococcal enterotoxin B (SEB)-induced steroid resistance in human peripheral blood mononuclear cells (PBMCs), and to investigate the potential mechanism of SEB superantigen-induced steroid resistance in vitro. METHODS: PBMCs were isolated from normal children blood by Ficoll-Hypaque gradient centrifugation and stimulated with SEB at different concentrations. The proliferation rate of cells was measured by MTT assay. The subcellular localization of glucocorticoid receptor α (GRα) was examined by confocal microscopy. Protein phosphorylation was measured by means of Western blotting. RESULTS: SEB induced steroid resistance in a range of 10-500 μg/L and no significant difference among concentrations was observed. In SEB-stimulated PBMCs, the GRα did not translocate to the nuclear after dexamethasone treatment. ERK inhibitor U0126 significantly attenuated the inhibition of GRα nuclear translocation in SEB-stimulated PBMCs. SEB also induced more rapid and sustained phosphorylation of ERK1/2 in PBMCs. CONCLUSION: This study demonstrates that SEB may contribute to steroid resistance through ERK pathway and is associated with abrogation of GRα nuclear translocation.