CD4 and acute lymphoblastic leukemia: The fourth cohort of recipient BALB/c mice was transplanted with 10 × 106 1 bone marrow cells and 2.5 × 106 CD4+ and 2.5 × 106 CD8+ T cells from WT C57BL/6 mice, and also given 2 × 105 B‐ALL‐ luc cells (group 4).