INVITRO SYNTHESIS OF IGE BY HUMAN-LYMPHOCYTES .4. SUPPRESSION OF THE SPONTANEOUS IGE SYNTHESIS BY IGE-BINDING FACTORS SECRETED BY TUNICAMYCIN-TREATED RPMI-8866 CELLS

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  • 1 January 1984
    • journal article
    • research article
    • Vol. 53  (4) , 783-790
Abstract
RPMI 8866 cells release IgE-binding factors (IgE-BF) capable of enhancing the spontaneous in vitro synthesis of IgE by purified B lymphocytes isolated from allergic individuals. In this study, the influence of tunicamycin, an inhibitor of protein glycosylation, on RPMI 8866 cells was investigated with regard to: the expression of surface receptors for IgE (Fc.epsilon.R), the release of IgE-BF into the culture supernatants and the biological activity of IgE-BF. After preincubation for 60 min with tunicamycin (1 .mu.g/ml), RPMI 8866 cells were cultured for 48 h in HB 101 serum-free medium; the culture supernatant was then filtered, concentrated and its biological activity was compared to that a parallel culture supernatant from untreated RPMI 8866 cells. Exposure of RPMI 8866 cells to tunicamycin resulted in: a reduction of surface Fc.epsilon.R, no effect on the release of IgE-BF into the culture supernatant and 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-BF secreted by tunicamycin-treated cells had no effect on the production of IgG, IgA or IgM by normal or Epstein-Barr virus-transformed B cells.