PHASE-CONTRAST MICROSCOPIC STUDIES USING CINEMATOGRAPHIC TECHNIQUES AND SCANNING ELECTRON-MICROSCOPY ON IGE-MEDIATED DEGRANULATION OF CULTURED HUMAN MAST-CELLS

Background Isolating human mast cells is a laborious procedure. Recent ly, cultured human mast cells raised from umbilical cord blood cells h ave become available. It is necessary to investigate whether IgE-media ted activation of these cells is mediated by exocytosis. Objective To verify IEE-mediated activation of these cultured human mast cells morp hologically. Methods The mast cells were raised from human umbilical c ord blood cells in the presence of stem cell factor and interleukin-6. IgE-sensitized cultured human mast cells were activated by anti-IgE, and morphological changes of the cells were examined under phase-contr ast microscopy using cinematographic techniques and scanning electron microscopy. Histamine release from the cells was measured with high-pe rformance liquid chromatography. Results Under the condition in which a significant histamine release was observed from the mast cells, phas e-contrast microscopy showed that the cultured human mast cells became swollen and extruded granules. Scanning electron microscopy disclosed the extrusion of smooth and round bodies from pores formed on the act ivated mast cell surface. Conclusion IgE-mediated histamine release fr om cultured human mast cells is accompanied by exocytosis morphologica lly, indicating that cultured human mast cells will help in studying t he functional properties of human mast cells.