A humanized mast cell system fixing human IgE:
Use for screening of immunological and chemical reagents endowed with anaphylactogenic or anti-degranulating properties
Inventors: U. Blank, F. Marchand, S. Mécheri, C. Tkaczyk and A. Weyer
Description of invention:
Human basophils and mast cells express high affinity IgE receptors (FceR1) composed of 3 subunits among which an a chain responsible for the binding of the IgE ligand. During an allergic reaction, allergen-specific IgE bound to these receptors becomes cross-linked by the multivalent allergen, thus triggering the release of inflammatory mediators, such as histamine. The difficulty of making cell donors available and the great interhuman variability in basophil response are considered major drawbacks for using human cells to screen anti-degranulating agents.
The E5 transfectant is a cultured rat mast cell line transfected with the a chain of the human FceR1 receptor. Incubation of this transfectant with human IgE (the binding of which is species-specific) induces expression of the human a chain at the cell surface, thus allowing to test for the receptor binding and inducing ability of human IgE. Once receptors are expressed, the transfectant can also be used to test the functional capability of bound IgE to trigger degranulation after incubation with anti-IgE or specific allergen, by measuring ß-hexosaminidase secretion.
This tool can be used in:
1. Routine laboratory investigation for diagnostic or research purposes: identification of allergen-specific IgE antibodies, characterization of the allergenicity of environmental substances, and search for autoantibodies against IgE or FceRI.
2. Cosmetic industry: this cell line allows detection of allergic reactions in individuals who have experienced cosmetic-related undesirable dermatologic reactions following cosmetics exposure
3. Pharmaceutical industry: to identify new drugs or immunologic reagents with potential anti-allergic activity.
4. Food processing industry: safety evaluation of newly introduced procedures in food processing (physical treatments, chemical additives...)
5. Clinical trials: assessement of the efficacy of anti-allergic immunotherapy (anti-allergic vaccination)
6. Industry producing allergen extracts for human use (desensitisation protocols): standardization of allergenic extracts
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