Staphylococcal enterotoxin B compromises the immune tolerant status in the airway mucosa

Background The breakdown of immune tolerance plays a critical role in allergic disorders; the mechanism of breaching immune tolerance remains largely unknown. Objective The present study aimed to investigate the role of Staphylococcal enterotoxin B (SEB) in the interference of the immune tolerance in the nasal mucosa. Methods The immune tolerant components, tolerogenic dendritic cells (TolDC) and regulatory T cells (Treg), were assessed in the surgically removed nasal mucosa from patients with allergic rhinitis (AR) or non-AR chronic rhinitis. The contents of SEB and integrin alphavbeta6 (avb6) in the nasal epithelium were assessed using enzyme-linked immunoassay. The ability of avb6 on TolDC induction and the effect of SEB on suppression of avb6 in nasal epithelial cells were observed in cell culture. Results Compared with that in the non-AR nasal mucosa, the frequencies of TolDCs/Tregs were lower, the contents of SEB were higher and the contents of avb6 were lower in the AR nasal mucosa. Avb6 had the ability to induce the development of TolDCs in vitro; the latter had the ability to induce Treg development. The expression of avb6 was detected in nasal epithelial cells in culture that could be suppressed by SEB. Conclusions and clinical relevance The components of immune tolerance machinery, TolDCs and Tregs were suppressed in the AR nasal mucosa. The increases in SEB and decreases in avb6 in nasal epithelium are associated with the compromises of immune tolerance in the nasal mucosa. SEB has the ability to suppress the expression of avb6 in nasal epithelial cells.