In vivo depletion of γδ T cells from recipients reduces GVHD severity. Five days before BMT, mice were depleted of γδ T cells by intraperitoneal injection of anti-TCR γδ mAb. Three days later, iIELs were collected from mice treated with anti-TCR γδ mAb or control Ab and stained with PE-anti-γδ (A). γδ T-cell-depleted and sham-depleted mice received transplants from BALB/c (γδ T-cell-depleted: ▴, n = 13; sham-depleted: •, n = 13) or syngeneic B6 donors (γδ T-cell-depleted: ▵, n = 6; sham-depleted: ○, n = 6) as in Figure 1 and evaluated for survival (B) and clinical GVHD score (C). Data from 2 similar experiments are combined. Error bars represent standard error. ▴ vs •, ^**P < .01 by Wilcoxon rank test. ▴ vs •, ^*P < .05 by Mann-Whitney U test.