Tcms are endowed with marked tolerance induction capabilities, and persist in vivo at least 1 year after BMT. (A) Lethally irradiated (10 Gy) C3H (H-2^K) mice received 1.25 × 10⁴ syngeneic HTCs. Mice then received a transplant of 3 × 10⁶ BALB/c-NUDE BM cells (H-2^d,BA-NU BM) in the presence or absence of different doses of (C3H × BALB/c)F1 (H-2^Kd, C3BF1) purified CD8⁺ Tcms. Data were pooled from 6 independent experiments. (B) Graft rejection model was established as in panel A. Mice received a transplant of 3 × 10⁶ BALB/c-NUDE BM cells (H-2^d, BA-NU BM) in the presence or absence of 5 × 10⁶ (C3H × BALB/c)F1 (H-2^Kd, C3BF1) purified Tcms or 1 × 10⁷ (C3H × BALB/c)F1 CTLs. Data were pooled from 5 independent experiments. (C) Peripheral blood levels of Tcms were analyzed 1 year after BMT by FACS measuring H2K^kH2D^d double-positive cells in the CD8⁺ gate. The figure shows representative mice of 7 mice that received a transplant of BM only (BM alone) or 7 mice that received a transplant of BM + HTCs + 5 × 10⁶ (C3H × BALB/c)F1 CD8⁺ Tcms (BM + Tcms).