Depletion of H₂O₂ by BL cell lines. The ability of BL cell lines to degrade H₂O₂ (peroxidase-like activity) was assessed as described in the Materials and Methods. A concentration of 100 μmol/L H₂O₂ was added to each cell suspension (5 × 10⁵ cells/mL). After various times of incubation at 37°C, aliquots were removed and the medium was assayed for the presence of residual H₂O₂ . The X's show the stability of H₂O₂ incubated in medium in the absence of cells. (▵) ST-486; (○) CA-46; (•) BJAB; (⋄) JD-38; (▪) EW-36; (□) JLP 119; (×) H₂O₂ only.