Membrane IgE binds and activates FcεRI in an antigen-independent manner

Luca Vangelista, Elisa Soprana, Michela Cesco-Gaspere, Paola Mandiola, Giulia Di Lullo, Rita N. Fucci, Franca Codazzi, Alessio Palini, Giovanni Paganelli, Oscar R. Burrone, Antonio G. Siccardi

Research output: Contribution to journalArticlepeer-review


Interaction of secretory IgE with FcεRI Is the prerequisite for allergen-driven cellular responses, fundamental events in immediate and chronic allergic manifestations. Previous studies reported the binding of soluble FcεRIα to membrane IgE exposed on B cells. In this study, the functional Interaction between human membrane IgE and human FcεRI is presented. Four different IgE versions were expressed in mouse B cell lines, namely: a truncation at the Cε2-Cε3 junction of membrane IgE isoform long, membrane IgE isoform long (without Igα/Igβ BCR accessory proteins), and both εBCRs (containing membrane IgE isoforms short and long). All membrane IgE versions activated a rat basophilic leukemia cell line transfected with human FcεRI, as detected by measuring the release of both preformed and newly synthesized mediators. The interaction led also to Ca 2+ responses in the basophil cell line, while membrane IgE-FcεRI complexes were detected by immunoprecipitation. FcεRI activation by membrane IgE occurs in an Ag-independent manner. Noteworthily, human peripheral blood basophils and monocytes also were activated upon contact with cells bearing membrane IgE. In humans, the presence of FcεRI in several cellular entities suggests a possible membrane IgE-FcεRI-driven cell-cell dialogue, with likely implications for IgE homeostasis in physiology and pathology.

Original languageEnglish
Pages (from-to)5602-5611
Number of pages10
JournalJournal of Immunology
Issue number9
Publication statusPublished - May 1 2005

ASJC Scopus subject areas

  • Immunology


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