Donor treatment of αDR3 decreases T-cell infiltration into GVHD target tissues. αDR3 or isotype mAb-treated gfp⁺ CD45.1⁺ C57BL/6 mice were used as T cell donors and BMT was performed. Gut (distal ileum) and liver were harvested from recipients on days 7 (A-B) and 14 (C-D). (A,C) Representative fluorescence microscopic images of gut (upper) and liver (lower) are shown. The scale bar represents 200 μm. The frequencies of donor gfp⁺ T cells into gut (B, left; D, left) and liver (B, right; D, right) were calculated (αDR3 vs isotype mAb; **P < .01, ***P < .001, ****P < .0001). These are the combined results of 3 experiments (Gut, n = 15 [day 7], 9 [day 14] for isotype and n = 14 [day 7], 9 [day 14] for αDR3 group; Liver, n = 13 [day 7], 9 [day 14] for isotype and n = 13 [day 7], 8 [day 14] for αDR3 group).