A total of 2.5 Â10 5 cells were incubated with 5 mM Trx1 (SBP-CCCCC) and 200 mM DTT for 30 min at 371C, washed three times and incubated with 250 ng/ml recombinant CD30L-His 10 (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).