PURIFIED RAT PERITONEAL MAST-CELLS - CHARACTERISTICS OF THE REMOVAL AND BINDING OF IGE

Mast cells were purified by discontinuous density gradient centrifugat ion to greater than 90% and subsequently exposed to lactic acid in ord er to dissociate endogenous IgE. Unfortunately no removal of this IgE was achieved, despite previous reports of lactic acid exposure dissoci ating IgE from human basophils. Only a minimal level of endogenous IgE was found on the surface of mast cells, however, which allowed invest igations of IgE binding to proceed without the initial removal of this endogenous IgE. Conditions for binding of normal rat IgE and myeloma IgE were established while efforts to bind human IgE to purified rat m ast cells were unsuccessful. Our results suggest that while purified r at mast cells have the potential to play an important role in the stud y of the IgE requirement of various stimuli including histamine-releas ing factor, this role is limited at present.