PRODUCTION OF GRANULOCYTIC COLONY-STIMULA TING FACTOR BY STROMAL POPULATIONS OF THE BONE-MARROW

Passaged bone marrow fibroblasts (PBMF) fail to maintain long-term hem opoiesis in culture unlike stromal adhesive layers of long-term cultur e of the bone marrow (LTCBM). What differs PBMF from LTCBM stromal cel ls in terms of the above ability we attempted to find out using immuno cytochemical microscopy and flow cytometry. There were no differences as to protein production of the extracellular matrix, production of gr anulocytic-macrophagal colony-stimulating factor, stem cell factor, tr ansforming growth factor beta, interleukine-1beta and interleukine-6. The difference lies in inability of PBMF to produce granulocytic colon y-stimulating factor (GCSF). It is evident that production of GCSF by stromal cells of the bone marrow is essential for maintenance of myelo poiesis in LTCBM.