Fig. 1
The redox regulation of T-cell state. Activated phagocytes produce H2O2 via NOX-2. H2O2 either oxidizes thiols (SH-) on the surface of T cells or enters inside T cells. Intracellularly, H2O2 either oxidizes glutathione (GSH) or interferes with DNA synthesis. Activated phagocytes and dendritic cells (DC) secrete cysteine (Cys) to the extracellular space. Cys is taken up by T cells and converted to GSH. GSH keeps surface thiols in the reduced state, neutralizes intracellular H2O2, and enables DNA synthesis. TCR-peptide-MHC interaction leads to the secretion of thioredoxin (TRX) by T cells, DCs, and Tregs. TRX helps to keep surface thiols in the reduced state. Black solid arrow indicates production, black dashed arrows indicate import/export, green solid arrows indicate activation, red bar-headed lines indicate inhibition.