Skin graft survival when the donor Treg cells and allograft differ in major or minor alloantigens. Eight- to 12-week-old B6 IL-2Rβ^−/− mice that were adoptively treated with the indicated population of Treg cells at birth (denoted as the donor Treg strain→IL-2Rβ^−/− recipient strain) received BALB/c, C3H, B6^bm3, and B6^bm12 (A) or BALB/c, BALB.B, B6, and C3H (B) skin grafts. (A) Tolerance to B6^bm3 skin. (B) Tolerance to BALB.B skin. The number of mice/group from a single experiment and the MST of allogeneic skin grafts are listed within each panel of the figure.