(a-e) BALB/c (allogeneic) or B6 (syngeneic) recipients were irradiated with 800cGy and intravenously given 5.0×106 B6 wt BM and either 5.0×105 wt B6 or Sema4D−/− T cells. n=4syn, n=6 allogeneic control, n=6 Sema4D−/− (a-c) Pathology scores of GVHD target organs on day +60 post BMT as described in materials and methods of (a) liver (b) small and large intestine, and (c) skin. (d) Splenic cellularity on d+60 post BMT. (e) Donor (H2b) CD3+, CD4+ and CD8+ from recipient spleens on d+60. Syngeneic recipients (white bars), allogeneic B6 wt Tc (black bars) and allogeneic recipients of Sema4D −/− B6 Tc recipients (gray bars). One of two similar experiments. *p<0.03