LYL8 depletion significantly decreases GVHD mortality, yet retains antitumor activity. Lethally irradiated BALB.B mice underwent transplantation on day -1 with 1 × 10⁵ F9 cells and on day 0 with 5 × 10⁶ B6 TCD-BM cells and 1.5 × 10⁶ CD3⁺ B6 T cells. Survival was followed for 60 days and is plotted as Kaplan-Meier curves (representative of 2 combined experiments for each condition). (A) ○ indicates no T cells (n = 8); □, nondepleted (n = 6); ♦, LYL8-depleted (n = 12); ▪, HSV8 control-depleted (n = 10). Depletion was 97.5% efficient in these transplants. ♦ versus ○, P < .001; ♦ versus □, P < .001; ♦ versus ▪, P < .001; ▪ versus ○, P = ns; □ versus ○, P = ns; ▪ versus □, P = ns. (B) Cause of death for recipient mice of the combined transplants plotted in panel A as determined by clinical evaluation and autopsy (gray bars indicates tumor; filled bars, GVHD).