Superantigens and cystic fibrosis: Resistance of presenting cells to dexamethasone

Staphylococcus aureus, a common pulmonary pathogen in cystic fibrosis (CF), produces exotoxins that are extremely potent superantigens. A number of an imal studies have shown that superantigens cause pulmonary inflammation, bu t the possible role of superantigens in CF has not been investigated. The p resent study assessed possible differences between control and CF B cells i n presenting superantigens to T cells. Immortalized B-cell lines were used as superantigen-presenting cells to avoid environmental influences (e.g., i nfection or antibiotics) common to freshly isolated cells. The results show that CF B-cell lines presented a staphylococcal superantigen to the immort alized T-cell line (Jurkat) as effectively as did control B-cell lines as m easured by interleukin-2 production. However, in contrast to the case for c ontrol B-cell lines, dexamethasone did not inhibit CF B-cell lines from pre senting superantigen. The resistance of superantigen-presenting CF B cells to corticosteroids suggests that the pulmonary response to superantigens ma y be poorly regulated in CF, leading to an exaggerated inflammatory respons e to S. aureus.