Small oligomers of immunoglobulin E (IgE) cause large-scale clustering of IgE receptors on the surface of rat basophilic leukemia cells

We examined the distribution of small oligomers of IgE bound to rat basophilic leukemia cells using fluorescence microscopy. The oligomers were seen to cluster into visible patches on the cell surface at 4 degrees C; at higher temperatures internalization also was observed. In contrast, cells labeled with IgE monomers remained predominantly ring- stained. Evidence is provided that the observed clustering of IgE oligomers is a cell-induced phenomenon, and the possible significance of this clustering is discussed in the context of the oligomer- triggered degranulation of rat basophilic leukemia cells.