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