Jurkat T cell Trx-1 secretion is reduced but surface thiol levels remain unchanged after intracellular glutathione depletion. (A) Trx-1 secreted into the media over a 24 hour treatment with BSO (25 μM) was analysed by competition ELISA. (B) Surface thiols were analysed on Jurkat T cells after treatment with BSO (25 μM for 24 hours) using FITC-conjugated maleimide and analysed by flow cytometry. (C) Compared with buthionine sulfoximine treatment (BSO; 25 μM; 48 hours), diethylmaleate (DEM; 20 μM; 48 hours) and cycloheximide (CHM; 0.1 μg/ml; 48 hours) also depleted intracellular glutathione as determined by the DTNB recycling assay. Intracellular GSH loss was associated with a decrease in Trx-1 secretion determined by competition ELISA (D) but surface thiols analysed bby FITC-maleimide labelling and flow cytometry remained unaffected (E). Data represents the mean +/− SEM where * represents p < 0.05 by unpaired t test with Welch’s correction for unequal variances or # represents p < 0.05, ## p < 0.01 and ### p < 0.001 by ANOVA.