Which one of the following antibodies is produced in response to allergy?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → IgE
Allergy is an exaggerated response of the immune system to a harmless substance in the surroundings, such as pollen, dust mites or animal dander. Such a substance is called an allergen. Mast cells release histamine and serotonin, which cause sneezing, watery eyes and a running nose.
(1) IgA — Incorrect. IgA is the antibody present in secretions such as colostrum, the first milk. It protects the infant.
(2) IgG — Incorrect. IgG is the most plentiful antibody in the blood and fights infections. It can also cross the placenta from mother to foetus.
(3) IgE — Correct. The antibodies made against allergens are of the IgE type.
(4) IgM — Incorrect. IgM is the first antibody produced when an infection begins. It is not the allergy antibody.
Note: The same question was also asked in CUET (UG) 2025 on 02-06-2025 (Slot 2), and a similar question in CUET (UG) 2023 on 05-06-2023 (Slot 2).
NCERT Extract:
Allergies –
