Graft-infiltrating DN T cells can suppress and kill antidonor CD8⁺ T cells.

(A) Graft-infiltrating cells were collected from 14 L^d+skin grafts of DLI-treated mice, stained to determine the proportion of DN T cells, and used as suppressor cells. Naive 1B2⁺CD8⁺ T cells were used as responders. Shown is the mean proliferation in counts/minute for 3 replicates. (B) Graft-infiltrating cells were collected as described for panel A and were depleted of CD4⁺ and CD8⁺ T cells. The enriched DN T cells were stimulated overnight and used as effector cells in a cytotoxicity assay. Activated 1B2⁺CD8⁺ (anti-L^d; ▾) and BW5147 (third-party; ▪) cells were used as targets. Shown is the mean percentage of specific killing ± SD of target cells for 3 replicates.