During Type I hypersensitivities, the first encounter with an antigen sensitizes the immune system. What class of antibodies are produced and what cells do they bind to?

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Multiple Choice

During Type I hypersensitivities, the first encounter with an antigen sensitizes the immune system. What class of antibodies are produced and what cells do they bind to?

In Type I hypersensitivity, the first exposure causes B cells to switch to producing IgE antibodies. These IgE molecules bind with high affinity to FcεRI receptors on mast cells and basophils, effectively arming these cells. Upon a subsequent encounter with the allergen, the antigen cross-links the bound IgE, triggering rapid degranulation and release of histamine and other mediators that produce the allergic symptoms. Other antibody classes have different roles (IgG in opsonization and complement, IgA in mucosal defense), so the combination of IgE with mast cells and basophils best explains the immediate reaction.

In Type I hypersensitivity, the first exposure causes B cells to switch to producing IgE antibodies. These IgE molecules bind with high affinity to FcεRI receptors on mast cells and basophils, effectively arming these cells. Upon a subsequent encounter with the allergen, the antigen cross-links the bound IgE, triggering rapid degranulation and release of histamine and other mediators that produce the allergic symptoms. Other antibody classes have different roles (IgG in opsonization and complement, IgA in mucosal defense), so the combination of IgE with mast cells and basophils best explains the immediate reaction.

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