Question

In an immediate allergic response, antibodies of the ___ class are first produced in response to allergen exposure. These antibodies then bind to receptors on ___ in tissues, as well as to other cells in the blood.

1. IgE; Mast cells
2. IgA; T cells
3. IgG; B cells
4. IgM; Macrophages

Answer 1

In an immediate allergic response, IgE antibodies are first produced and bind to mast cells. The correct answer is 1. IgE; Mast cells. These cells release histamine and other substances that cause allergy symptoms upon subsequent allergen exposure.

Step-by-step explanation:

In an immediate allergic response, antibodies of the IgE class are first produced in response to allergen exposure. These antibodies then bind to receptors on mast cells in tissues, as well as to other cells in the blood. Therefore, the correct answer is 1. IgE; Mast cells. Upon initial exposure to a potential allergen, an allergic individual synthesizes IgE antibodies via the typical process of antigen-presenting cells presenting processed antigen to T cells, which then stimulate B cells to produce IgE. The constant domain of the IgE molecules interacts with mast cells embedded in connective tissues. When there is a subsequent exposure to the same allergen, IgE molecules on mast cells bind the antigen and cause the mast cell to release histamine and other modulators, which are key contributors to the symptoms of an allergy.