Allergen structures and epitopes.

Human type 1 hypersensitivity diseases such as allergic rhinoconjunctivitis are characterized by allergen-specific IgE antibodies produced in allergic individuals after allergen exposure. IgE antibodies bound to receptors on the surface of effector cells trigger an allergic response by interacting with three-dimensional (conformational) epitopes on the allergen surface. Crystal structures are available for complexes of antibody specifically bound to five allergens, from birch pollen, bee venom, cockroach, cow's milk and timothy grass pollen. The details of the antibody-allergen interaction extending all the way to atomic resolution are available from such complexes. In vitro investigations using recombinant monoclonal antibodies and human basophils show that binding affinity is a key to triggering the allergic response. Continued molecular characterization of antibody-allergen interactions is paving the way for the use of recombinant allergens in allergen-specific diagnosis and immunotherapy.