Question

Hay fever that occurs when people are exposed to pollen involves an excess release of IgE, which binds to ________ and causes them to ________.

A) mast cells : degranulate, releasing histamine
B) pollen : stimulate the release of histamine
C) macrophages : destroy the pollen whose by-products stimulate histamine release
D) T helper cells : stimulate the proliferation of cytotoxic T cells
E) mast cells : stimulate the proliferation of cytotoxic T cells

Answer 1

Hay fever is caused by an excess release of IgE, which binds to mast cells, leading them to degranulate and release histamine, causing allergy symptoms.

Step-by-step explanation:

When people with hay fever are exposed to pollen, an excess release of IgE antibodies is triggered. These IgE antibodies bind to mast cells via their Fc receptor. When pollen, the specific allergen, binds to the IgE on the mast cells, this induces cross-linking of the IgE molecules. This process activates the mast cells, leading to degranulation. During degranulation, mast cells release their granules containing histamine and other inflammatory molecules into the extracellular environment, which in turn causes the symptoms associated with hay fever.