Which immunoglobulin class binds to mast cells and basophils?

The immunoglobulin class that binds to mast cells and basophils is IgE. This antibody plays a crucial role in the immune response, particularly in allergic reactions and responses to parasitic infections. When IgE binds to its high-affinity receptor (FcεRI) on the surface of mast cells and basophils, it sensitizes these cells. Upon subsequent exposure to the same allergen, the cross-linking of bound IgE antibodies triggers the degranulation of these cells, leading to the release of histamine and other mediators that contribute to allergic symptoms.

Understanding the role of IgE is particularly important in the context of allergic diseases, such as asthma, hay fever, and anaphylaxis, where IgE-mediated responses are central. In contrast, other immunoglobulin classes, like IgM, IgD, and IgG, have distinct roles in the immune system that do not involve direct binding to mast cells and basophils in the context of immediate hypersensitivity reactions.