Q.82 Match the class of antibodies to appropriate description or function
Antibodies Description / function
(i) IgA (p) Mucosal immunity
(ii) IgG (q) Immunity to parasitic infections
(iii) IgD (r) Most abundant antibody in the blood
(iv) IgE (s) Found on the B cell membranes
(A) (i)–(s), (ii)–(r), (iii)–(q), (iv)–(p) (B) (i)–(p), (ii)–(q), (iii)–(s), (iv)–(r)
(C) (i)–(p), (ii)–(r), (iii)–(s), (iv)–(q) (D) (i)–(p), (ii)–(s), (iii)–(q), (iv)–(r)
Correct Answer: (C) (i)-(p), (ii)-(r), (iii)-(s), (iv)-(q)
IgA provides mucosal immunity, IgG is the most abundant antibody in blood, IgD functions on B cell membranes, and IgE mediates immunity to parasitic infections.
Antibody Functions
IgA (i) is the primary antibody in mucosal surfaces like the gut and respiratory tract, forming secretory IgA to neutralize pathogens without inflammation. IgG (ii) constitutes 75-80% of serum antibodies, enabling opsonization, complement activation, and placental transfer. IgD (iii) serves as a B cell receptor on mature naive B cells alongside IgM, aiding antigen recognition and cell maturation. IgE (iv) binds mast cells and eosinophils to trigger defenses against helminths via degranulation.
Option Analysis
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(A) (i)-(s), (ii)-(r), (iii)-(q), (iv)-(p): Incorrect; IgA matches mucosal immunity (p), not B cell membranes (s); IgD matches (s), not parasites (q).
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(B) (i)-(p), (ii)-(q), (iii)-(s), (iv)-(r): Incorrect; IgG is abundant in blood (r), not parasites (q); IgE matches parasites (q).
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(C) (i)-(p), (ii)-(r), (iii)-(s), (iv)-(q): Correct; all matches align with standard functions.
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(D) (i)-(p), (ii)-(s), (iii)-(q), (iv)-(r): Incorrect; IgG is serum-abundant (r), not B cell-specific (s).
Antibodies, or immunoglobulins, are key to adaptive immunity, with each class—IgA, IgG, IgD, IgE—serving distinct roles crucial for CSIR NET life sciences preparation. Understanding how to match class of antibodies to function IgA IgG IgD IgE helps in tackling immunology MCQs effectively.
Core Matches
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IgA – Mucosal Immunity: Secretory IgA dominates mucosal surfaces, preventing pathogen entry in saliva, tears, and gut.
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IgG – Most Abundant in Blood: Comprises 75-80% of serum Ig, crosses placenta for fetal protection.
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IgD – B Cell Membranes: Acts as BCR on naive B cells for antigen sensing and maturation.
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IgE – Parasitic Infections: Triggers eosinophil/mast cell response against helminths.
Exam Relevance
For CSIR NET, focus on these pairings to solve matching questions accurately, as they test immunoglobulin isotype functions. Practice reinforces concepts like class switching and effector roles.
