Figure 2. IgE-mediated Th2 and Mast cell/basophil activation and inhibitory effects of allergen-specific IgG and -IgA as well as anti-IgE.
Inhibition of IgE-mediated Th2-cell activation (left panel) and basophil/mast cell degranulation (right panel) by allergen-specific IgG and -IgA (purple), and anti-IgE (red) treatment. Whereas allergen-specific IgG and IgA compete with IgE for binding to allergens, anti-IgE antibodies bind to IgE and block binding of IgE to both the high affinity (FcεRI) and low affinity (CD23) receptors for IgE expressed on antigen presenting cells and basophils/mast cells. In this way they can inhibit IgE-mediated activation of allergen-specific T cells as well as the release of inflammatory mediators by basophils/mast cells induced by IgE-mediated crosslinking of FcεRI after allergen exposure