Anti-OPN Ab reduces donor T-cell survival. C3H.SW CD8⁺ T cells (CD45.2⁺CD8⁺) were labeled with CFSE and injected into lethally irradiated recipient mice accompanied by donor TCD BM. These recipients were treated with anti-OPN Ab or control IgG (200 μg/mouse) at days 0, 3, and 6 after transplantation. The donor-derived CD8⁺ T cells were recovered from liver and spleen of the recipients at day 7 after transplantation. Their CFSE dilution was analyzed by flow cytometry. Data were represented as CFSE histograms (A) and as the percentages of the cells from spleen with given number of divisions (B). P < .05. Alloreactive donor-derived CD8⁺ T cells were recovered from GVHD recipients at day 14 after transplantation, labeled with CFSE, and adoptively transferred into secondary recipients treated with anti-OPN Ab or control IgG. These cells were then recovered from secondary recipients 72 hours after adoptive transplantation, and fluorescence intensities of CFSE were analyzed (C). Donor-derived CD8⁺ T cells were recovered at day 14 after transplantation from GVHD recipients treated with anti-OPN Ab or control IgG. Apoptosis of those cells were observed by staining with annexin V and propidium iodide (PI) (D). MFI indicates mean fluorescence intensity. Results were representative of 5 mice for each group of 3 independent experiments. *P < .05.