Recipients that received transplants of marrow and CD4⁺CD25⁺T cells acutely reject third-party skin grafts but accept skin grafts from marrow donor and recipient background mice. Three to 4 months after BMT, chimeric BALB/c recipients of B6 BM and CD4⁺CD25⁺ T cells (n = 13, A), BALB/c mice that did not receive transplants (n = 8, B), and B6 mice that did not receive transplants (n = 5, C) received tail skin grafts from donor (B6, ♦), host (BALB/c, ▪), or third-party (C3H/HeJ, •) background mice. Data are pooled from 3 individual experiments.