What type of antibodies characterize IgE-mediated hypersensitivity reactions?

IgE-mediated hypersensitivity reactions are characterized by the production of IgE antibodies. These reactions are typically associated with allergic responses and parasitic infections. When an individual is exposed to an allergen, the immune system can mistakenly identify it as harmful, leading to the production of IgE antibodies. These antibodies bind to allergens and also attach to mast cells and basophils, which can then release inflammatory mediators such as histamine upon subsequent exposures to the allergen. This mechanism is responsible for the symptoms seen in allergic reactions, such as asthma, hay fever, and anaphylaxis.

Other antibody types like IgA, IgD, IgG, and IgM play various roles in the immune response, but they are not the primary actors in IgE-mediated hypersensitivity reactions. Thus, the distinctive feature of IgE is its specific involvement in these types of hypersensitivity, making it the correct answer.