GAS-binding proteins are activated normally by IL-2 stimulation in thiol-deficient medium. EMSA were performed, using GAS motif-containing probes, SIE and FcγRI, on nuclear extracts of NK3.3 cells (3 × 10⁶/condition) that had been IL-2–deprived and precultured for 12 hours in medium in the presence or absence of L-cystine and GSH followed by stimulation with IL-2 (200 U/mL, 15 minutes). No difference was seen in GAS-binding activities between cells cultured in the thiol-deficient compared to thiol-sufficient medium.