Figure 3.

Super-crosslinking of allergen by allergen-specific polyclonal IgG. Upon entry e.g., through the epithelium, allergen is complexed by allergen-specific polyclonal IgG. The resulting multimeric allergen complex is able to (A) induce B cell activation by crosslinking membrane bound IgE present in form of the B cell receptor (BCR) on the surface of IgE⁺ memory B cells. This may result in activation of memory B cells in the absence of cognate T cell help and their differentiation into short-lived and long-lived plasma cells or may (B) induce basophil or mast cell activation by cross-linking of the FcεRI bound IgE molecules.