Final answer:
Helper T cells (TH) are responsible for allergy reactions by triggering the production of IgE antibodies upon exposure to allergens.
Explanation:
Helper T cells (TH) are largely responsible for hypersensitivity (allergy) reactions.
During type I hypersensitivity responses, on first exposure to an allergen, allergen epitopes are presented to TH2 cells, leading to the production of IgE antibodies that trigger allergic reactions.
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