[The production of granulocyte colony-stimulating factor by stromal bone marrow populations]

Passaged bone marrow fibroblasts (PBMF) fail to maintain long-term hemopoiesis in culture unlike stromal adhesive layers of long-term culture of the bone marrow (LTCBM). What differs PBMF from LTCBM stromal cells in terms of the above ability we attempted to find out using immunocytochemical microscopy and flow cytometry. There were no differences as to protein production of the extracellular matrix, production of granulocytic-macrophagal colony-stimulating factor, stem cell factor, transforming growth factor beta, interleukin-1 beta and interleukin-6. The difference lies in inability of PBMF to produce granulocytic colony-stimulating factor (GCSF). It is evident that production of GCSF by stromal cells of the bone marrow is essential for maintenance of myelopoiesis in LTCBM.