Both CD4⁺ and CD8⁺ T cells are required for maximal GVL effects of delayed DLI in MCs. Data were pooled from 2 independent experiments. (A) B10.A + B6 → B6 MCs received 3 × 10⁷ nondepleted CD4⁺CD8⁺ DLIs (*, n = 15; inoculum contained a total of 5.2 × 10⁶ CD4⁺ plus 2.5 × 10⁶ CD8⁺ T cells), CD4^–CD8⁺ DLI (▴, n = 14; inoculum contained 2.5 × 10⁶ CD8⁺ T cells), CD4⁺CD8^– DLI (▿, n = 13; inoculum contained 5.2 × 10⁶ CD4⁺ T cells), CD4^–CD8^– DLI (○, n = 13), or no DLI (□, n = 13) on day 56 after BMT. All mice received 1 × 10³ EL4 T leukemia cells on day 63. (B) MCs received 3 × 10⁷ B10.A nondepleted CD4⁺CD8⁺ DLIs (*, n = 16; inoculum contained a total of 5.7 × 10⁶ CD4⁺ plus 2.3 × 10⁶ CD8⁺ T cells), CD4^–CD8⁺ DLI (▴, n = 16; inoculum contained 2.3 × 10⁶ CD8⁺ T cells), CD4⁺CD8^– DLI (▿, n = 16; inoculum contained 5.8 × 10⁶ CD4⁺ T cells), CD4^–CD8^– DLI (○, n = 13), or no DLI (□, n = 14) on day 56 after BMT followed by 5 × 10⁴ C1498 myeloid leukemia cells on day 63.