Inhibiting Tim-3 increases allogeneic T-cell proliferation. (A) MLR was performed by mixing B6-purified T cells with irradiated BALB/c stimulators (1:1) and αTim-3. These cultures were pulsed with [³H]thymidine on the indicated days and harvested 16 hours later. Proliferation was determined as a measure of radioactive uptake. One-way ANOVA with Tukey multiple comparison test (P < .001, n = 5 per group). ■ indicates control IgG; and ○, αTim-3 5D12 mAb. (B) CFSE-labeled WT or Tim-3^−/− BALB/c purified T cells (10⁷) were transferred into lethally irradiated CD45.1⁺ congenic B6 recipients. Spleens were harvested and analyzed by flow cytometry for CFSE dilution and on days 3 and 4. Representative histograms shown are representative of 4 mice per group per day. Filled histogram, WT donor; open histogram, Tim-3^−/− donor. Cells were gated on CD45.1⁺, H2K^d positive, CD4 or CD8 positive events.