In vitro generated mast cells investigated by monoclonal antibodies.

In the present study we have investigated the development of mast cells under in vitro conditions after depletion of mature mast cells of male Wistar rats by intraperitoneal application of distilled water. The studies were carried out both by monoclonal antibodies (MAb) against rat peritoneal mast cells and by cytochemical techniques. During cultivation the amount of MAb-positive cells increased from less than 5% to 64% after 3 weeks, which was accompanied by increased histamine levels and cell size. After 2 weeks the first Alcian blue stained mast cells were detectable, while safranin-positive granules appeared only after 3 weeks. These findings suggest that there are mast cell precursors in the peritoneum which may differentiate into mature mast cells. The antigen on the cell surface recognized by the MAb seems to be expressed during mast cell maturation.