Synergistic effects of murine stem cell factor in combination with a variety of cytokines on the expansion of murine hematopoietic progenitor cells in short-term suspension cultures.

In the present study, it is represented that the ability of murine stem cell factor (SCF) to expand hematopoietic progenitor cells in short-term suspension culture when used alone or with IL-1 beta, IL-3, IL-6, M-CSF and IL1 beta Plus IL-3. SCF alone had a limited effect on the expansion of early primitive hematopoietic progenitor cells (CFU-HPP: high proliferative potential colony forming unit, and CFU-S: colony forming unit in spleen) even at a high concentration, but expanded mature hematopoietic progenitor cells (CFU-GM: colony forming unit-granulocyte/macrophage, and BFU-E: burst forming unit-erythroid) markedly at low concentrations. When SCF was used in combination with other cytokines, the expansion of primitive hematopoietic progenitor cells was significantly increased; namely, CFU-HPP were expanded approximately 2 to 5-fold compared with SCF alone. A marked expansion of hematopoietic progenitor cells was observed in a combination of SCF plus IL-1 beta plus IL-3. In this setting, CFU-S was increased 2.2-fold compared with the number of CFU-S in fresh bone marrow and CFU-HPP were increased 8.5-fold compared with the number of primary CFU-HPP. These results suggest that these factors may be utilized in experiments of murine bone marrow transplantation (BMT) and also in human BMT. Namely, the adequate number of hematopoiesic progenitor cells and stem cells required for the successful engraftment can be obtained from small volume of peripheral or bone marrow blood by this procedure, thus obtiating the donor's burden.