Sarfati M, Rector E, Sehon A H, Delespesse G
Immunology. 1984 Dec;53(4):783-90.
It was previously shown that RPMI 8866 cells released IgE-binding factors (IgE-BFs) capable of enhancing the spontaneous in vitro synthesis of IgE by purified B lymphocytes isolated from allergic individuals. In the present study, the influence of tunicamycin, an inhibitor of protein glycosylation, on RPMI 8866 cells was investigated with regard to: (i) the expression of surface receptors for IgE; (ii) the release of IgE-BFs into the culture supernatants, and (iii) the biological activity of IgE-BFs. After preincubation for 60 min with tunicamycin (1 microgram/ml), RPMI 8866 cells were cultured for 48 hr in HB 101 serum-free medium; the culture supernatant was then filtered, concentrated, and its biological activity was compared to that of a parallel culture supernatant from untreated RPMI 8866 cells. The results of these experiments indicate that exposure of RPMI 8866 cells to tunicamycin resulted in: (i) a reduction of surface Fc epsilon R; (ii) no effect on the release of IgE-BFs into the culture supernatant, and (iii) the conversion of IgE-potentiating factors into IgE-suppressing factors. The latter factors suppressed the IgE secretion by U266 myeloma cells and completely inhibited the activity of IgE-potentiating factors on B lymphocytes from allergic individuals. IgE-BFs secreted by tunicamycin-treated cells had no effect on the production of IgG, IgA or IgM by normal or EBV-transformed B cells.
先前的研究表明，RPMI 8866细胞可释放IgE结合因子（IgE-BFs），该因子能够增强从过敏个体中分离出的纯化B淋巴细胞体外自发合成IgE的能力。在本研究中，研究了蛋白质糖基化抑制剂衣霉素对RPMI 8866细胞的影响，具体涉及：（i）IgE表面受体的表达；（ii）IgE-BFs释放到培养上清液中的情况；以及（iii）IgE-BFs的生物活性。用衣霉素（1微克/毫升）预孵育60分钟后，将RPMI 8866细胞在HB 101无血清培养基中培养48小时；然后将培养上清液过滤、浓缩，并将其生物活性与未处理的RPMI 8866细胞的平行培养上清液进行比较。这些实验结果表明，RPMI 8866细胞暴露于衣霉素会导致：（i）表面FcεR减少；（ii）对IgE-BFs释放到培养上清液中没有影响；以及（iii）IgE增强因子转化为IgE抑制因子。后一种因子抑制了U266骨髓瘤细胞的IgE分泌，并完全抑制了IgE增强因子对过敏个体B淋巴细胞的活性。经衣霉素处理的细胞分泌的IgE-BFs对正常或EBV转化的B细胞产生IgG、IgA或IgM没有影响。
