Humanized Mediator Release Assay as a Read-Out for Allergen Potency

Area of Science:

• Immunology
• Cell Biology

Background:

• Mediator release assays are crucial for studying allergic reactions in vitro.
• These assays mimic in vivo degranulation upon allergen exposure.
• They are used to assess allergenicity and patient serum reactivity.

Purpose of the Study:

• To describe a simple, robust, and sensitive 2-day protocol for an in vitro mediator release assay.
• To utilize a humanized rat basophil leukemia cell line expressing the human high-affinity IgE receptor (FcεRI).
• To provide a cell-based system for analyzing allergen-induced degranulation without antigen immobilization.

Main Methods:

• Passive sensitization of humanized rat basophil leukemia cells with human serum.
• Stimulation of cells with serial dilutions of allergens to induce mediator release.
• Quantification of β-hexosaminidase release as a surrogate marker for degranulation.

Main Results:

• The described protocol is a sensitive, reproducible, and robust cell-based system.
• The assay effectively measures allergen-IgE cross-linking-induced cell degranulation.
• It offers a valuable tool for various applications in allergy research.

Conclusions:

• The assay is a useful tool for standardizing allergen extracts and comparing patient reactivity.
• It aids in investigating allergen potency, variants (e.g., hypoallergenicity), and ligand effects.
• The assay can monitor treatment efficacy in allergen immunotherapy.