Mechanism of histamine release from rat isolated peritoneal mast cells by dextran: The role of immunoglobulin E

Abstract

In vivo passive sensitization of rat peritoneal mast cells withNippostrongylus braziliensis antiserum or rat monoclonal myeloma IgE greatly enhanced histamine releasein vitro by dextran or anti IgE, but did not alter release by compound 48/80 or A23187. Conversely, removal of IgE from the cells by acid pH abolished histamine release by dextran and anti IgE but did not impair release by compound 48/80. Whereas, histamine release from cells isolated from rats genetically resistant to dextran (NR rats) by anti IgE was potentiated by passive sensitization, dextran was unable to stimulate secretion from control or sensitized NR cells. The results suggest that dextran releases histamine by interaction with cell-fixed IgE and that the NR mast cell membrane lacks the ability to interpret this stimulus.