CD30L binding assay
A total of 2.5 × 105 cells were incubated with 5 μM Trx1 (SBP-CCCCC) and 200 μM DTT for 30 min at 37°C, washed three times and incubated with 250 ng/ml recombinant CD30L-His10 (R&D Systems) for 10 min at RT. After washing, cells were stained with anti-polyHis monoclonal antibody (Sigma) followed by incubation with R-PE-conjugated goat F(ab')2 anti-mouse Ig's (Biosource).