Serum-free culture of human megakaryocyte progenitors

A serum-free method for the culture of megakaryocyte progenitor cells (burst-forming units megakaryocyte, BFU-Mk) from human bone marrow is described, using recombinant cytokines (interleukin[IL]-3, IL-6, IL-11 and stem cell factor [SCF]) to provide megakaryocyte colony-stimulating activity. IL-3 alone, but not IL-6, IL-11 or SCF alone, promoted BFU-Mk formation. The combination of IL-3 with IL-11 or with IL-6+SCF was necessary for optimal maturation of the megakaryocytes. No significant difference in BFU-Mk numbers was found between the combinations of IL-3+IL-11 and IL-3+IL-6+SCF. The development of BFU-Mk was found to be maximal at 12-14 d. Using these conditions, normal ranges for human bone marrow BFU-Mk were derived which may provide the basis for studying megakaryocyte colony growth in pathological conditions.