H2O2 potently inhibits T lymphocyte migration to CXCL11. (A) SEB-activated T cell migration toward either basal or increasing concentrations of H2O2. **p < 0.01. (B) Basal or CXCL11 (10 nM)-induced migration of SEB-activated T cells pretreated with increasing concentrations of H2O2. *p < 0.05, **p < 0.01, ***p < 0.001. (C) Basal or chemokine-induced migration of SEB-activated T cells pretreated with indicated concentrations of catalase. *p < 0.05, ##p < 0.01, ###p < 0.001. (D) SEB-activated T cells pretreated with H2O2 (100 μM) migration toward increasing concentrations of CXCL11. *p < 0.05, **p < 0.01, ***p < 0.001. (E) Basal or CXCL11 (10 nM)-induced migration of SEB-activated T cells pretreated with increasing concentrations of the superoxide dismutase mimetic Mn(III)tetrakis(4-benzoic acid)porphyrin chloride. *p < 0.05, **p < 0.01, ***p < 0.001. (F) Basal or CXCL10 (10 nM)-induced migration of SEB-activated T cells pretreated with increasing concentrations of H2O2. *p < 0.05, **p < 0.01. (G) Basal or CXCL12 (10 nM)-induced migration of SEB-activated T cells pretreated with increasing concentrations of H2O2. *p < 0.05, **p < 0.01. For all graphs, migrated cells were counted using flow cytometry; data are the mean values ± SEM of three or four independent experiments.