Transfer of naive CD4⁺ T cells from CCR6-deficient mice to MHC-matched/mhc-mismatched recipients delays GvHD onset and reduces severity of symptoms. The time course of symptom development is shown for (A) ear inflammation; (B) erythrosquamous skin lesions; (C) percentage of mice showing diarrhea; (D) changes in body weight; and (E) survival curves. Mean values ± SD are shown from 1 experiment representative of 3 independent transfer experiments in which recipient mice were reconstituted with 0.35 × 10⁶ MHC-matched/mhc-mismatched WT CD4⁺CD45RB^high naive T cells (○, n = 37) or CCR6-deficient CD4⁺CD45RB^high naive T cells (□,n = 57). Results are also shown of body weight change (F) and ear inflammation (G) from control experiments in which naive (▵) BALB/c CD4⁺ T cells were transferred to CB17-SCID recipient mice. Statistical analyses were performed as in Figure 1, obtaining the P values shown in the panels. (A) P < .001 (day 19 ACT). (H) Representative hematoxylin/eosin–stained dorsal skin sections of T-cell recipients from WT or CCR6-deficient donors, taken at days 12 and 28 ACT. The image was obtained with a Leica Leitz DMRB microscope (Solms, Germany) with 10× and 4× objective lenses, using a COHU High Performance camera (San Diego, CA) and Adobe Photoshop (San Jose, CA) software for image processing.