Which term defines a substance that triggers an allergic reaction?

Which term defines a substance that triggers an allergic reaction?

• A. Allergen
• B. Enzyme
• C. Antibody
• D. Irritant

Answer: (A)

Allergens are substances that trigger allergic reactions. In someone with allergies, the immune system overreacts to typically harmless things like pollen, foods, or pet dander. The body makes specific IgE antibodies to the allergen, and on subsequent exposures the allergen binds to those antibodies on mast cells, releasing histamine and other chemicals that cause symptoms such as itching, swelling, or breathing trouble. Enzymes are catalysts that speed up chemical reactions, not triggers of allergy. Antibodies are parts of the immune response, not the substance that starts it. An irritant causes irritation through non-immune means, not through an allergic reaction. So the correct term for the substance that triggers an allergic reaction is allergen.

Allergens are substances that trigger allergic reactions. In someone with allergies, the immune system overreacts to typically harmless things like pollen, foods, or pet dander. The body makes specific IgE antibodies to the allergen, and on subsequent exposures the allergen binds to those antibodies on mast cells, releasing histamine and other chemicals that cause symptoms such as itching, swelling, or breathing trouble. Enzymes are catalysts that speed up chemical reactions, not triggers of allergy. Antibodies are parts of the immune response, not the substance that starts it. An irritant causes irritation through non-immune means, not through an allergic reaction. So the correct term for the substance that triggers an allergic reaction is allergen.