Membrane IgE binds and activates Fc epsilon RI in an antigen-independent manner.
J Immunol
; 174(9): 5602-11, 2005 May 01.
Article
em En
| MEDLINE
| ID: mdl-15843559
ABSTRACT
Interaction of secretory IgE with FcepsilonRI is the prerequisite for allergen-driven cellular responses, fundamental events in immediate and chronic allergic manifestations. Previous studies reported the binding of soluble FcepsilonRIalpha to membrane IgE exposed on B cells. In this study, the functional interaction between human membrane IgE and human FcepsilonRI is presented. Four different IgE versions were expressed in mouse B cell lines, namely a truncation at the Cepsilon2-Cepsilon3 junction of membrane IgE isoform long, membrane IgE isoform long (without Igalpha/Igbeta BCR accessory proteins), and both epsilonBCRs (containing membrane IgE isoforms short and long). All membrane IgE versions activated a rat basophilic leukemia cell line transfected with human FcepsilonRI, 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-FcepsilonRI complexes were detected by immunoprecipitation. FcepsilonRI 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 FcepsilonRI in several cellular entities suggests a possible membrane IgE-FcepsilonRI-driven cell-cell dialogue, with likely implications for IgE homeostasis in physiology and pathology.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Imunoglobulina E
/
Receptores de Antígenos de Linfócitos B
/
Receptores de IgE
/
Antígenos
Limite:
Animals
/
Humans
Idioma:
En
Revista:
J Immunol
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Itália