In vitro clonal growth of normal hematopoietic cells from a leukemic environment. Two weeks after transplantation, the mice were killed and BM was harvested. The normal hematopoietic cells (CD45.1⁺GFP⁻)were doubly sorted with near 100% purity for in vitro clonal assays (A). For the CFC assay to measure committed HPCs (B), the sorted CD45.1⁺GFP⁻ cells were cultured in the defined methylcellulose medium supplemented with a cytokine cocktail. Mix, GM, G, M, and E represent CFC-mix (> 2 lineages), CFC-granulocyte/monocyte, CFC-granulocyte, CFC-monocyte, and BFU-erythrocyte, respectively. Values are mean ± SD. *P < .05 (t test). **P < .01 (t test). In addition, the CAFC assay with limiting dilution at day 35 during the long-term culture was used to measure the more primitive hematopoietic cells, and the result is shown as a representative dataset from 3 experiments with similar results (C).