Anti–third-party Tcms without GVH reactivity support engraftment of TDBM allografts in sublethally irradiated mice. Sublethally irradiated (5.5Gy) Balb/c (H-2^d) mice were transplanted with 20 × 10⁶ C57BL/6-nude (H-2^b) BM cells with or without: (A) Five × 10⁶ allogeneic C57BL/6 Tcm (H-2^b) or (B) 5 × 10⁶ CB6 F1 Tcms (H-2^bd). Percentage of donor cells in peripheral blood was analyzed 90 days after transplant by FACS using anti-donor (H-2K^b) antibodies. Data represent results of at least 3 independent experiments (***P < .001). (C) Average weight change during 100 days after transplant of nude-BM or nude-BM and allogeneic Tcms.