Question

Explain the mechanism of an allergic reaction.

Answer 1

Allergen:

1. An allergen is any substance that is responsible to cause an allergic reaction.

Mechanism of an allergic reaction:

1. When allergens enter the body, antigens are captured and presented to immune cells specifically to the T cells (in a similar manner as if the allergen was a foreign invading microbe).
2. The number of immune interactions occurs between T cells and B cells, and then B cells produce allergen-specific IgE antibodies.
3. Once antibodies are released into the blood, IgE interacts with mast cells (the major allergy immune cell), as well as other immune cells such as basophils.
4. Persons who are sensitised will develop an allergic reaction on re-exposure to the allergen.