Specific GvT effect mediated by CD8⁺cells. Spleen cells of [C57BL/6 × BALB/c]F₁ (H-2^b/d) recipients of transplants from BALB/c (H-2^d) donors were intravenously transferred into naive, lethally irradiated BALB/c mice simultaneously subjected to subcutaneous MethA (H-2^d) tumor cell inoculation. (A) MethA tumor growth after adoptive transfer of spleen cells from non-tumor-bearing (□) or MethA-bearing (•) primary transplant recipients (n = 5 per group). (B) Transfer of CD8-depleted (⋄) or nondepleted (•) spleen cells from MethA-bearing primary transplant recipients (n = 5 per group). (C) Same experiments as in panel B with NK cell-depleted (▵), CD4-depleted (×), or nondepleted (•) spleen cells from MethA-bearing primary transplant recipients (n = 5 per group). Notably, no GvHD was observed in secondary recipients after adoptive transfer of spleen cells. Data are presented as means ± SD. The results are representative of at least 2 independent series of experiments. ^*P < .05 versus respective control groups.