IgE receptors expressed on antigen presenting cells have been shown to facilitate the presentation of allergens in the presence of specific IgE, resulting in effective T cell activation at low allergen concentrations. It has been demonstrated with this assay that formation of allergen-IgE complexes increases with IgE clonality and allergen affinity. Interference with these IgE-dependent mechanisms by ‘blocking’ IgG antibodies may down regulate T cell responses and manifest as a reduction in allergic responses and long-term clinical tolerance.

The IgE-FAB assay represents an in vitro model of facilitated allergen presentation. Allergen-IgE complexes are incubated with an EBV-transformed B cell line and complexes bound to CD23 on the surface of cells are detected by flow cytometry.

Principle of the FAB-assay

  1. Allergen-serum complex binding
  2. Incubation of antibody/allergen complex with EBV-transformed B cells
  3. Bounded complexes to CD23 on cell surface are stained with anti-IgE
  4. Analyze IgE levels by flow cytometry


This assay is suitable for monitoring inhibitory antibody function from patients receiving allergen-specific immunotherapy.

Contact us for any questions or support with projects that you might have. We can be of assistance during the whole process from start to finish of a study.