Dependence of non-alloantigen-mediated graft-versus-tumor activity on CD8 T cells and on perforin and FasL-mediated cytotoxicity. (A) MCA205 (H-2^b) tumor growth in [C57BL/6 × BALB/c]F₁ (H-2^b/d) recipients of transplants from syngeneic F₁ donors (▵, negative control) or allogeneic wild-type (•), CD8^-/- (♦), and CD4^-/- (□) C57BL/6 (H-2^b) donors (n = 6 per group). (B) Splenic lymphocytes of MCA205 tumor-bearing F₁ recipients of transplants from either wild-type (•), perforin^-/- (+), or FasL-deficient (⋄) C57BL/6 donors were adoptively transferred into irradiated naive C57BL/6 mice. These secondary recipients were simultaneously subjected to subcutaneous MCA205 (H-2^b) tumor cell inoculation. The transferable GvT effect was significantly impaired by both perforin and FasL deficiency (n = 3 per group). Data are presented as means ± SD. ^*P < .05 for C57BL/6 wild-type donors versus syngeneic F₁ donors and allogeneic CD8^-/-, perforin^-/-, and FasL-deficient C57BL/6 donors, separately.