Question

Match LIST-I with LIST-II

LIST-I (Immunoglobulin Class)		LIST-II (Characteristics)
A. IgG	I. Serves as part of B-cell receptor complex
B. IgA	II. Anaphylactic mediating antibody
C. IgD	III. Most abundant in body fluid, neutralize toxins, opsonizes bacteria
D. IgE	IV. Secretory antibody and protect mucous membrane

Choose the correct answer from the options given below:

• A. A-I, B-II, C - III, D - IV
• B. A-I, B - III, C - II, D - IV
• C. A-I, BII, C - IV, D - III
• D. A-III, B - IV, C - I, D - II

Hint:

Use the mnemonic "GAME-D" to remember the isotypes. \textbf{G} is the most abundant and goes everywhere. \textbf{A} is in secretions ("secretory"). \textbf{M} is the first responder (not in this list). \textbf{E} is for allergy ("Eeeek! a bee!"). \textbf{D} is a receptor on B-cells.

Answer 1

The Correct Option is D

Step 1: Concept Overview:
This question tests your knowledge of the five immunoglobulin (antibody) isotypes and their key functions.
Step 2: Detailed Explanation:
Here's a breakdown of each immunoglobulin class and its corresponding characteristic:


A. IgG: The most prevalent immunoglobulin in serum and bodily fluids. It neutralizes toxins, opsonizes pathogens to enhance phagocytosis, and activates the complement system. Matches III. Most abundant in body fluid, neutralize toxins, opsonizes bacteria.

B. IgA: Predominantly found in secretions like mucus, saliva, tears, and breast milk. As a dimer, it protects mucosal surfaces. Matches IV. Secretary antibody and protect mucous membrane. (Note: "Secretary" should be "Secretory").

C. IgD: Present in low serum concentrations. Functions as an antigen receptor on mature, naive B-lymphocytes, forming part of the B-cell receptor (BCR) complex alongside IgM. Matches I. Serves as part of B-cell receptor complex.

D. IgE: Found in the lowest serum concentration, IgE is critical in allergic reactions (Type I hypersensitivity). It binds to mast cells and basophils; allergen cross-linking triggers the release of inflammatory mediators (e.g., histamine), causing anaphylaxis. Matches II. Anaphylactic mediating antibody.

Step 3: Conclusion:
The correct match is A-III, B-IV, C-I, D-II, corresponding to option (D).