CD4 cells alone mediate GVL. B6 mice were irradiated and reconstituted with T-cell-depleted C3H.SW BM, B6 mCP-CML with 0, 106, 2 × 106, or 4 × 106 C3H.SW CD4+ T cells. (A) Survival. P < .0001 comparing BM alone versus 1 × 106 CD4 cells analyzed to day 43 after transplantation. (B) Serial flow cytometry of peripheral blood. Mice were bled and cells were stained as described in “Materials and methods.” As in Figure 3, staining with anti-NGFR is shown in red, and isotype for NGFR is shown in blue. Isotype staining was not done on the sample with a single-color dot plot. Each row is a single mouse. Three and 2 representative mice are shown for the 2 × 106 and 1 × 106 CD8 doses to capture the types of responses we saw. The middle 2 × 106 mouse nearly clears mCP-CML at day 41, but it returns by day 72 after transplantation. Note that mCP-CML develops prior to its elimination by donor CD4 cells.
