The receptor for immunoglobulin E on rat basophilic leukemia cells: effect of ligand binding on receptor expression.

We have evaluated the effect of ligand binding on expression of the receptor for IgE on rat basophilic leukemia (RBL) cells. RBL cells were grown in the presence or absence of 131I-labeled IgE and sometimes were also surface labeled with 125I. We found that cells grown in the presence of IgE continued to accumulate receptors at the surface and thus the apparent amount of cell-associated IgE continued to increase. The results obtained suggest that, in the presence of IgE, the elimination of the receptor from the surface was halted or slowed significantly (approximately equal to 80%) while insertion into the membrane of previously synthesized receptor continued.