Action of anti-mouse IgE on mouse and rat mast cells.

The action of anti-mouse IgE on normal or sensitized mouse and rat peritoneal mast cells as well as on the reaginic activity of mouse and rat antisera was studied. Anti-mouse IgE induced histamine release from normal mouse peritoneal mast cells in vitro and this effect was greatly enhanced when mast cells were actively sensitized. The action of anti-mouse IgE on normal rat peritoneal mast cells was slight; it was enhanced after sensitization of these cells with mouse reaginic antibodies as well as after active sensitization. Moreover, anti-mouse IgE is able to neutralise the reaginic activity of mouse and rat antisera. The results suggest that there exist some functional and structural similarities between mouse and rat IgE.