CD8 cells alone mediate GVL. B6 mice were irradiated and reconstituted with T-cell-depleted C3H.SW BM, B6 mCP-CML with 0, 2.5 × 105, 5 × 105, 106, 2 × 106, or 4 × 106 C3H.SW CD8+ T cells. (A) Survival. P < .003 for each CD8 recipient group versus BM alone. (B) Serial flow cytometry of peripheral blood. Mice were bled on days 10, 17, 24, and 31 after transplantation, and cells were stained with antibodies against the myeloid marker Gr-1 (except for day 31 when anti-CD11b was used) and anti-NGFR or an isotype control for NGFR. Shown are superimposed dot plots from anti-NGFR (red dots) and isotype for NGFR (blue dots) stained samples. Single-color dot plots indicate that an isotype control was not available. Each row is a representative single mouse. Results from 2 representative recipients of 1 × 106, 5 × 105, and 2.5 × 105 CD8 cells are shown to capture the types of responses we observed. Flow cytometry of blood, BM, and spleen cells at time of killing is presented for the same mice. Note that mCP-CML develops prior to its elimination by donor CD8 cells.
