A Child Is Stung by a Bee at the Beginning

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The Answer is The child did not have a reaction after the first bee sting because there was no immunoglobulin E specific for bee venom in the childʹs blood or tissues yet. After the first bee sting, mucosa-associated B cells and TH2 cells produced cytokines that induce B cells to make IgE antibodies against the bee venom. Rather than circulating like IgG or IgM, the allergen-specific IgE antibodies bind to IgE receptors on mast cells. Mast cells are nonmotile granulocytes associated with the connective tissue adjacent to capillaries throughout the body. With any subsequent exposure to the immunizing allergen, the mast cell-bound IgE molecules bind the antigen. Cross-linking of IgEs by an antigen triggers the release of soluble allergic mediators from the mast cells, a process called degranulation. These mediators cause allergic symptoms within minutes of antigen exposure. After initial sensitization by an allergen, the allergic child will respond to each subsequent exposure to the allergen. Therefore, only after the second bee sting did the child show the signs of type I hypersensitivity or anaphylaxis. The first bee sting sensitized the child to the venom.

A Child Is Stung by a Bee at the Beginning

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