Long term bone marrow culture

Long term bone marrow culture comprises a stromal layer and proliferating myeloid cells. Very large macrophages stained with F4/80 are a major part of the stromal layer. Smaller, round F4/80-positive cells can be seen attached to the stromal cells. An example is seen in centre field. These are proliferating promonocytes. The other cells attached to the F4/80-positive stromal cells in this view are profilerating granulocyte precursors.