IL-18 receptor 1-deficient donor T cells have differential effects on CD4⁺- and CD8⁺-mediated acute GVHD-related mortality. (A) B6D2F1 mice underwent irradiation with 13 Gy TBI and transplantation with 5 × 10⁶ TCD BM from allogeneic wild-type B6 donors plus 2 × 10⁶ CD3⁺ T cells from wild-type B6 or IL-18r1-/-mice, respectively (□, n = 6; ▪, n = 6). Syngeneic recipients (▴, n = 5) underwent transplantation with cells from F1 donors. Data from 1 of 2 similar experiments are shown. Percentage survival after BMT in allogeneic recipients □ vs ▪; P = .01. (B) bm1 underwent irradiation and transplantation with TCD BM from allogeneic wild-type B6 and 2 × 10⁶ CD8⁺ T cells from wild-type B6 (○, n = 6) or IL-18r1-/-mice (•, n = 6). Syngeneic recipients (▴, n = 3) underwent transplantation, as described in “Materials and methods.” Data from 1 of 2 experiments are shown. Percentage survival of allogeneic recipients after BMT, ○ vs •; P = .05. (C) B6D2F1 mice underwent irradiation with 11 Gy TBI and transplantation with 5 × 10⁶ TCD BM and were purified with 2 × 10⁶ CD8⁺ T cells from allogeneic B6 donors and were injected with IL-18 (•, n = 10) or the diluent (○, n = 10), as described in “Materials and methods.” Syngeneic recipients (▾, n = 4) underwent transplantation with cells from F1 donors. Percentage survival after BMT in allogeneic recipients ○ vs •; P = NS.