Low Affinity IgE Receptors: Regulation and Functional Roles in Cell Activation

  1. Derek J. Chadwick Organizer,
  2. David Evered Organizer and
  3. Julie Whelan
  1. Junji Yodoi Faculty of Medicine,
  2. Masaya Hosoda,
  3. Yasuhiro Maeda,
  4. Seiji Sato,
  5. Masaaki Takami and
  6. Takumi Kawabe

Published Online: 28 SEP 2007

DOI: 10.1002/9780470513866.ch9

Ciba Foundation Symposium 147 - IgE, Mast Cells and the Allergic Response

Ciba Foundation Symposium 147 - IgE, Mast Cells and the Allergic Response

How to Cite

Yodoi, J., Hosoda, M., Maeda, Y., Sato, S., Takami, M. and Kawabe, T. (2007) Low Affinity IgE Receptors: Regulation and Functional Roles in Cell Activation, in Ciba Foundation Symposium 147 - IgE, Mast Cells and the Allergic Response (eds D. J. Chadwick, D. Evered and J. Whelan), John Wiley & Sons, Ltd., Chichester, UK. doi: 10.1002/9780470513866.ch9

Author Information

  1. Institute of Immunology, Kyoto University, Yoshida, Sakyo, Kyoto 606, Japan

Publication History

  1. Published Online: 28 SEP 2007

ISBN Information

Print ISBN: 9780471923091

Online ISBN: 9780470513866

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Keywords:

  • low affinity IgE receptors;
  • regulation;
  • cell activation;
  • expression;
  • haemopoietic cells

Summary

The low affinity IgE receptors (FcεRII/CD23) homologous to animal lectins have the unique property of cleaving-off the extracytoplasmic portion as the soluble form (IgE binding factor; IgE-BF). Molecular analysis using FcεRIl/CD23 cDNA proved that FcεRII is not unique to B lymphocytes but is expressed on a variety of cell lineages including T lymphocytes, macrophages and eosinophils. In these cell types, IL-4 is a general inducer of this molecule while IFN-γ down-regulates B cell FcεRII/CD23 and up-regulates FcεRII/CD23 on macrophage and eosinophil cell lines. As predicted by the expression of FcεRII/CD23 in some HTLV-I(+) T cell lines, FcεRII/CD23 proved t o be induced on normal peripheral T lymphocytes by IL-4 or IL-2 in the presence of additional permissive signals. As indicated by IL-2-dependent FcεRII/CD23 induction, there is an interesting bilateral co-regulation between FcεRII/CD23 and the 55 kDa chain of the IL-2 receptor complex with Tac antigen (IL-2R/p55(Tac)). Triggering of FcεRII/CD23 resulted in the enhanced expression of IL-2R/p55(Tac), whereas IL-2 enhanced the expression of FcεRII/CD23 in some systems. It is suggested that the triggering of cell surface FcεRII/CD23 by natural ligands is effectively buffered by soluble FcεRII/CD23 (IgE-BF).