Recipients of β₇^-/- donor T cells have less GVHD mortality and morbidity. (A) Lethally irradiated (1300 cGy) B10.BR recipients underwent transplantation with 5 × 10⁶ WT TCD BM and either 1 × 10⁶ WT (□) or β₇^-/- (▴) splenic T cells. Survival from 3 combined experiments (n = 30) is depicted as a Kaplan-Meier curve. Statistical analysis: ▴ versus □ (P = < .04). (B) Clinical GVHD score curve is shown for mice (A), again representing 3 combined experiments (n = 30), where □ versus ▴ (P = .023). (C) Lethally irradiated (1300 cGy) B10.BR recipients underwent transplantation with 5 × 10⁶ WT TCD BM only and 2 × 10⁶ WT (□) or β₇^-/- (▴) splenic T cells or 3 × 10⁶ WT (♦) or β₇^-/- (+) splenic T cells. Statistical analysis: ▴ versus □ (P = NS), ♦ versus + (P = NS). TCD BM only group (n = 4), 2 × 10⁶ WT or β₇^-/- T cells group (n = 8), 3 × 10⁶ WT or β₇^-/- T cells group (n = 5).