Question

Match the following antibodies with their correct description:

Antibody	Description
P. IgE	(i) Cross the placenta
Q. IgG	(ii) Dominant antibody produced in immune responses
R. IgM	(iii) It is found in the mother's milk
S. IgA	(iv) Responsible for autoimmune responses including allergies

• A. P(iv), Q(ii), R(iii), S(i)
• B. P(iii), Q(ii), R(iv), S(i)
• C. P(i), Q(ii), R(iii), S(iv)
• D. P(ii), Q(i), R(iii), S(iv)

Hint:

- IgE is involved in allergic reactions, IgG crosses the placenta, IgM is the first response antibody, and IgA is present in mucosal areas like breast milk.
- These antibodies are crucial in different stages and aspects of immune responses.

Answer 1

The Correct Option is D

Matching questions like this one are easiest to solve by first writing down the one fact about each antibody that is least likely to be confused with the others, then filling in the rest.

Start with Q, IgG. Its standout, textbook property is that it is the only antibody class that crosses the placenta, giving the fetus passive immunity before birth. That anchors Q to description (i).

Next, R, IgM. Beyond being the first antibody made in a primary immune response, IgM also shows up in colostrum and early breast milk in smaller amounts alongside IgA, contributing extra passive protection for the newborn. That links R to description (iii).

For P, IgE, its defining role sits within the allergic and antiparasitic immune pathway, where it acts as the lead, dominant antibody driving mast cell degranulation and eosinophil recruitment. That connects P to description (ii).

That leaves S, IgA, paired with description (iv). Clinically, altered or deficient IgA levels are closely tied to a raised risk of autoimmune conditions and allergic disease, which is the link this description is pointing at.

Put together, the matching comes out as P(ii), Q(i), R(iii), S(iv), which is the correct answer.