Which class of antibodies is primarily involved in allergic reactions?

The correct answer is IgE, as this class of antibodies plays a crucial role in the body's immune response to allergens. IgE is primarily associated with allergic reactions and the defense against parasitic infections. When an allergen enters the body, it can trigger the production of IgE antibodies by B cells. These IgE antibodies then bind to allergens and activate mast cells and basophils, leading to the release of histamines and other inflammatory mediators.

This process results in the symptoms commonly associated with allergies, such as itching, swelling, and bronchoconstriction, which are part of the immediate hypersensitivity reactions. IgE's specific association with allergies distinguishes it from the other antibody classes, which serve different roles in the immune system. For example, IgG primarily functions in fighting bacterial and viral infections, IgA is predominantly found in mucosal areas and bodily secretions, and IgM is typically the first antibody produced in response to an infection but is not directly involved in allergic reactions.