MsrB1 is needed for the ability of DCs to induce CD4 T-cell proliferation and activation. carboxyfluorescein succinimidyl ester (CFSE)-stained OT-II cells were cocultured for 3 days with WT and MsrB1−/− BMDCs that had been loaded with 0, 10, 25, or 50 μg/mL ovalbumin (OVA) (n = 3 per group). The CFSE dilution (A) and CD25 and CD44 expression (B) of the OT-II cells were measured by flow cytometry with gating on the side scatter (SSC)low T cell-receptor (TCR)-β+ cells in the live cells. Mean ± SEM are shown. * p < 0.05, ** p < 0.01; ns, not significant, as determined by unpaired t-test. The data are representative of two independent experiments, both of which had similar results.