GANGLIOSIDE GM3 INHIBITS INTERLEUKIN-3-DEPENDENT BONE-MARROW-DERIVED MAST-CELL PROLIFERATION

To investigate the modulated proliferation of an interleukin-3 (IL-3)- dependent cell by exogenous ganglioside GM3, mouse bone marrow-derived mast cells (BMMC) were cultured with various concentrations of GM3 in the presence of IL-3. By 4 weeks of culture, most of the nonadherent cells were alcian blue-positive mast cells. Culturing 2-week-cultured BMMC with GM3 for 1 week reduced the number of alcian blue-positive ce lls, but the increased total histamine content of BMMC was observed. T o examine the effect of GM3 on the synergistic response by IL-3 and in terleukin-4 (IL-4), 3-week-cultured BMMC were cultured with GM3 in the presence of IL-3 and IL-4 for 1 week. Although the addition of IL-4 t o culture medium increased the number of BMMC, treatment with GM3 redu ced its proliferative activity. Concerning the effect of GM3 on cell m embrane, there are no changes in the expression of lgE receptors on BM MC treated with GM3 though a low concentration of GM3 increased it. Ho wever, the production of tumor necrosis factor-alpha from BMMC treated with GM3 was significantly suppressed. These results indicate that in vitro treatment with exogenous GM3 inhibited the proliferative respon se of IL-3-dependent mast cell populations and modulated its character istics.