Bone marrow stromal cell line promotes the proliferation of mast cell progenitors derived from cord blood CD34+ cells under serum-free conditions with a combination of both cell-cell interaction and soluble factors.

A higher production of functional mast cells (MCs) can be generated by co-culturing cord blood-derived CD34+ cells with a human bone marrow stromal cell line under serum-free conditions supplemented with stem cell factor and IL-6. We addressed the question of whether the higher proliferation of MCs in this co-culture system might be due to the higher proliferation of MC progenitors. The stromal cell line increased the cell numbers of MC progenitors derived from cord blood-derived CD34+ cells, in a combination of cell-cell interactions between stromal cells and CD34+ cells, and as yet unidentified soluble factors derived from stromal cells.