EFFECT OF INTERLEUKIN-3 ON THE DIFFERENTIATION AND HISTAMINE CONTENT OF CULTURED BONE-MARROW MAST-CELLS

Mouse bone marrow hematopoietic stem cells were isolated from mouse femur bone and cultured in RPMI 1640 supplemented medium with 20 units/ml of the purified T-cell lymphokine, interleukin 3 (IL-3). IL-3 was uniquely able to induce the proliferation and differentiation of mature mast cells in vitro. The sparse granulation of the bone marrow-derived mast cells (BMMC) can be seen by day 5, progressing to definable mast cells by day 7, the mast cells appear morphologically mature and comprise a 96% pure population after 14 days of the culture. The monocytes/macrophages, eosinophils and neutrophils disappeared by day 9. After 4 weeks of tissue culture, mast cells are fully mature and completely granulated at 98% cell purity. The BMMC are mononuclear, oval or round in shape and appear smaller than rat peritoneal mast cells. BMMC are stable over 3-5 months in conditioned medium. The homogeneous mast cell population possesses membrane receptors and mediators, such as histamine in their metachromatic granules. The histamine content of BMMC in culture between 2 to 4 weeks rose from 1.43 to 1.82 pg/cell. Moreover, the percentage of histamine release caused by 0.1 μM and 1.0 μM ionophore A23187 was 15% and 35%, respectively. By contrast, the histamine releasing activity of 0.01% and 0.001% compound 48/80 were 12±2% and 59±7% respectively. The granular density, histamine content and histamine release activity of BMMC are different from that of peritoneal mast cells. © 1990 Birkhäuser Verlag.