Figure 7. Human BM CD34⁺ cells require G-CSF to generate B lineage cells in stromal cell-free cultures.

(A) 1×10⁴ cells/ml CB CD34⁺ cells or the indicated concentrations of BM CD34⁺ cells were cultured in the presence of SCF, FL and IL-7 for 4 weeks. Lymphoid cells were identified by flow cytometry and the results are given as numbers of CD19⁺ cells generated / input progenitor cell. (B) BM CD34⁺ cells (5×10⁴ cells/ml) were cultured alone or with the indicated cytokines. After 4 weeks of culture, CD19 expression of the recovered cells was assessed by flow cytometry. (C,D) BM CD34⁺ cells (5×10⁴ cells/ml) (C) or CB CD34⁺ cells (1×10⁴ cells/ml) (D) were cultured for 4 weeks in the indicated combinations of SCF (S), FL (F), IL-7 (7) and/or G-CSF (G). The results are given as mean total numbers of CD19⁺ cells recovered ± S.D. Similar results were obtained in three independent experiments.