Isersky C, Rivera J, Mims S, Triche T J
J Immunol. 1979 May;122(5):1926-36.
The present study investigates the fate of the cell-bound IgE by using a well-characterized rat basophilic leukemia cell line and a purifed IgE myeloma protein. Both histamine-releasing and nonreleasing cell lines were examined. In both cases, no evidence for cell-mediated IgE catabolism could be elicited. Both the dissociated IgE and the receptors remained intact for prolonged periods of time, as demonstrated by binding assays. Internalization and/or recycling of membrane-bound IgE could not be demonstrated by E. M. autoradiography. We found only limited time-dependent changes in accessibility to anti-IgE antibody, trypsin, or elution at low pH (2.9 to 3.1). A biphasic dissociation of cell-bound 125I-IgE during incubation in the presence of excess unlabeled IgE was reproducibly observed; the more slowly dissociated IgE was also less readily dissociated at pH 3.4. These studies lead us to conclude that, in vitro, IgE resides in a functional orientation on the surface of RBL-1 cells, for prolonged periods of time.
本研究通过使用一种特性明确的大鼠嗜碱性白血病细胞系和一种纯化的IgE骨髓瘤蛋白，来研究细胞结合型IgE的命运。对组胺释放型和非释放型细胞系均进行了检测。在这两种情况下，均未发现细胞介导的IgE分解代谢的证据。如结合试验所示，解离的IgE和受体在很长一段时间内均保持完整。电子显微镜放射自显影法未证实膜结合型IgE的内化和/或再循环。我们仅发现抗IgE抗体、胰蛋白酶或低pH值（2.9至3.1）洗脱的可及性随时间有有限的变化。在存在过量未标记IgE的情况下孵育期间，可重复观察到细胞结合型125I-IgE的双相解离；解离较慢的IgE在pH 3.4时也较难解离。这些研究使我们得出结论，在体外，IgE在RBL-1细胞表面以功能取向存在很长一段时间。
