CD25⁺ cells cultured under different conditions inhibit GVHD.

One million CD25-depleted B6 T cells were infused into nonirradiated, NK-depleted BALB/c SCID recipients. A second group of mice received a separate injection of 10⁶ CD25⁺ cells expanded as for Figure 6, with immobilized anti-CD3 mAb and high-dose IL-2 (open boxes). A third group of mice received a separate injection of 10⁶ CD25⁺ cells cultured with irradiated BALB/c splenocytes and high-dose IL-2 (open triangles). A fourth group of mice received a separate injection of 0.5 × 10⁶CD25⁺ cells cultured with irradiated BALB/c splenocytes, low-dose IL-2 and TGFβ as described in “Materials and methods” (star). On the x-axis are days after transfer of cells. On the y-axis is the proportion of recipients surviving (n = 6/group; allP values ≤ .016 compared to control group [closed circle]).