Characterization of the receptors for IgE on membranes isolated from rat basophilic leukemia cells

摘要: Abstract Mast cells, basophils and a tumor analog, rat basophilic leukemia have surface receptor for immunoglobulin E (IgE). Membranes from such cells should be highly useful the study of how α- β-subunits interact with plasma membrane function therein. were prepared cells. The reacted radioiodinated IgE to saturate fraction their receptors radiolabel was used as marker. When isolated sucrose gradients, 40 ± 10% yields membranes obtained these typically purified 13-fold regard cellular proteins. Unoccupied almost all recovered (as assessed on solubilized detergent) surface-labeled proteins in general. membrane-bound appeared fully exposed anti-IgE antibodies but surprisingly 70–80% unoccupied present unable bind when unsolubilized vesicles tested. By electron microscopy preparations free recognizable intracellular organelles. Though some multivesicular many showed large breaks continuity. Assessment permeability, carried out dextran indicated that significant number (⩾50%) IgE-carrying are not sealed. It is therefore most likely both external cytoplasmic aspects vesicles. Treatment trypsin or papain did alter apparent mol. wt α-chain its binding activity IgE. Additionally, examined by enzyme-catalysed iodination, no labeling observed under conditions where it labeled intact (i.e. presence IgE). These results suggest either does penetrate cannot modified particular probes we used.