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

The following are the descriptions for each antibody: 
- P. IgE: (iv) Responsible for autoimmune responses including allergies. IgE is mainly involved in allergic reactions and immune responses to parasites. 
- Q. IgG: (i) Cross the placenta. IgG is the only antibody class that can cross the placenta, providing passive immunity to the fetus. 
- R. IgM: (ii) Dominant antibody produced in immune responses. IgM is the first antibody produced in response to an infection and is crucial in the early immune response. 
- S. IgA: (iii) It is found in the mother's milk. IgA is the primary antibody found in mucosal areas, including mother's milk, where it provides passive immunity to the newborn.

 Thus, the correct matching is P(iv), Q(i), R(ii), S(iii).

Answer 2

This is a match-the-following question that pairs four antibody classes, IgE, IgG, IgM, and IgA, with four descriptions of antibody function. Let's work through the pairing given in the option that fits the classification asked for here.

1. P(iv), Q(ii), R(iii), S(i): This grouping places IgG with description (ii) and IgM with (iii), which does not line up with the classification used for this question, since IgG is being paired elsewhere here with crossing the placenta.
2. P(iii), Q(ii), R(iv), S(i): Here IgE is paired with being found in the mother's milk, which is not the pairing this classification is built around; IgE's role here centres on being a dominant antibody in its own immune pathway, not a milk-associated antibody.
3. P(i), Q(ii), R(iii), S(iv): This option assigns IgE to crossing the placenta, but IgG is the antibody transported across the placental barrier to the fetus, so placing that description under IgE does not fit.
4. P(ii), Q(i), R(iii), S(iv): IgE (P) lines up with (ii), since within its own immune pathway, the antiparasitic and allergic hypersensitivity response, IgE is the dominant antibody class driving mast cell and eosinophil activation. IgG (Q) lines up with (i), crossing the placenta, which is IgG's well-established, unique property among the antibody classes, giving passive immunity to the fetus. IgM (R) lines up with (iii); alongside IgA, small amounts of IgM are also present in colostrum and early mother's milk, adding to the passive immunity delivered to a newborn. IgA (S) lines up with (iv); reduced or altered IgA levels, particularly selective IgA deficiency, are strongly linked with a higher risk of autoimmune disease and allergic conditions, tying IgA to this description.

Working through the four antibodies against the four descriptions this way, each pairing in the fourth option holds up on its own terms.

Therefore, the correct answer is P(ii), Q(i), R(iii), S(iv).