An allergic reaction after a bee sting involves cross-linking of IgE on which cells?

An allergic reaction after a bee sting involves cross-linking of IgE on which cells?

• A. Basophils
• B. T lymphocytes
• C. Mast cells
• D. Neutrophils

Answer: (C)

IgE-mediated immediate hypersensitivity hinges on cross-linking of IgE bound to FcεRI receptors on mast cells. When a bee venom allergen enters, it binds to IgE already attached to mast cells in the skin and mucosa, causing the IgE molecules to cross-link. This triggers a signaling cascade that leads to degranulation and release of histamine and other mediators. Histamine then causes rapid vasodilation, increased vascular permeability, and smooth muscle effects, producing the quick-onset symptoms of an allergic reaction and, in severe cases, anaphylaxis. Basophils can also participate, but the primary tissue effector cells driving this immediate reaction are mast cells. Neutrophils and T lymphocytes do not mediate this IgE cross-linking.

IgE-mediated immediate hypersensitivity hinges on cross-linking of IgE bound to FcεRI receptors on mast cells. When a bee venom allergen enters, it binds to IgE already attached to mast cells in the skin and mucosa, causing the IgE molecules to cross-link. This triggers a signaling cascade that leads to degranulation and release of histamine and other mediators. Histamine then causes rapid vasodilation, increased vascular permeability, and smooth muscle effects, producing the quick-onset symptoms of an allergic reaction and, in severe cases, anaphylaxis. Basophils can also participate, but the primary tissue effector cells driving this immediate reaction are mast cells. Neutrophils and T lymphocytes do not mediate this IgE cross-linking.