FIGURE 2. Maintenance of CTL by Sema4D−/− T cells.

B6 wt (allogeneic H2^b) or Sema4D−/− (allogeneic H2^b) CD90+ T cells cells were cultured in vitro for 5 days with irradiated BALB/c (H2^d) splenocytes (a) or transplanted into irradiated BALB/c mice (b) as described in materials and methods. Splenocytes were harvested from the cultures on day +5-6 in the in vitro priming experiments (a) or from recipients (n=5/group) on day +14 after BMT. CTL assays, normalized for total donor (H2^b) CD8⁺ cells, and used in a ⁵¹Cr-release assay. Cytotoxic T lymphocyte activity against allo targets (P815) in wt allo-control (□) vs. Sema4D−/− allo (▲) groups. Lysis in allogeneic groups was similar, whereas no significant lysis of syngeneic targets (EL-4) observed in either of wt (●) or Sema4D−/− (◇)groups . Data from one of two similar experiments shown.