Anatomy of immune response MCQs With Answer

Anatomy of Immune Response MCQs With Answer

This quiz set is designed specifically for M.Pharm students to deepen understanding of the structural and functional anatomy of the immune response. It covers cellular players, molecular mediators, organ architecture, antigen recognition, signal transduction, and effector mechanisms that underpin innate and adaptive immunity. Questions emphasize mechanistic detail, clinical relevance, and implications for immunotherapeutics and vaccine design. Use these MCQs for revision, formative assessment, and to identify areas needing further reading. Each question includes concise options and the correct answer to help you consolidate knowledge and prepare for advanced exams in immunotechnology and related pharmaceutical sciences.

Q1. Which cell type is primarily responsible for antigen presentation to naïve CD4+ T cells in peripheral lymph nodes?

• Follicular dendritic cell
• Plasmacytoid dendritic cell
• Conventional dendritic cell (cDC) migrating from tissues
• Macrophage resident in the lymph node

Correct Answer: Conventional dendritic cell (cDC) migrating from tissues

Q2. Which MHC class and processing pathway most commonly presents peptides derived from intracellular viral proteins to CD8+ T cells?

• MHC class II via endosomal processing
• MHC class I via proteasomal degradation and TAP transport
• MHC class I via autophagy
• MHC class II via cross-presentation

Correct Answer: MHC class I via proteasomal degradation and TAP transport

Q3. In the germinal center reaction, which process predominantly increases antibody affinity for antigen?

• Class switch recombination
• Somatic hypermutation followed by selection
• V(D)J recombination in mature B cells
• Receptor editing in the bone marrow

Correct Answer: Somatic hypermutation followed by selection

Q4. Which cytokine pair is most important for differentiation of naïve CD4+ T cells into Th1 and Th2 lineages respectively?

• IL-6 for Th1 and IL-12 for Th2
• IL-12 for Th1 and IL-4 for Th2
• IFN-γ for Th1 and IL-17 for Th2
• TGF-β for Th1 and IL-10 for Th2

Correct Answer: IL-12 for Th1 and IL-4 for Th2

Q5. Which complement pathway can be initiated directly by antibodies bound to antigen and leads to a C3 convertase containing C4b2a?

• Alternative pathway
• Lectin pathway
• Classical pathway
• Properdin-stabilized pathway

Correct Answer: Classical pathway

Q6. Which receptor on phagocytes recognizes the Fc region of IgG to mediate opsonization and phagocytosis?

• Toll-like receptor 4 (TLR4)
• Fcγ receptor (FcγR)
• Complement receptor 1 (CR1)
• Fcε receptor (FcεR)

Correct Answer: Fcγ receptor (FcγR)

Q7. During T cell development in the thymus, positive selection primarily tests for which property of developing thymocytes?

• Ability to bind self-peptide–MHC with moderate affinity
• Absence of autoreactive TCRs
• Expression of functional CD28 co-stimulatory receptor
• Ability to produce IL-2

Correct Answer: Ability to bind self-peptide–MHC with moderate affinity

Q8. Which immunoglobulin isotype is most effective at crossing the placenta to provide passive immunity to the fetus?

• IgM
• IgG
• IgA
• IgE

Correct Answer: IgG

Q9. Which pattern recognition receptor family is located intracellularly and primarily senses viral RNA to induce type I interferons?

• C-type lectin receptors (CLRs)
• Toll-like receptors (endosomal TLR3/7/8)
• NOD-like receptors (NLRs)
• RIG-I–like receptors (RLRs)

Correct Answer: RIG-I–like receptors (RLRs)

Q10. Which chemokine gradient is most important for naïve lymphocyte homing to high endothelial venules in lymph nodes?

• CXCL13 binding CXCR5
• CCL19/CCL21 binding CCR7
• CXCL8 binding CXCR1/2
• CCL2 binding CCR2

Correct Answer: CCL19/CCL21 binding CCR7

Q11. Which intracellular signaling motif on the T cell receptor complex associates with ZAP-70 after ITAM phosphorylation?

• Immunoreceptor tyrosine-based inhibitory motif (ITIM)
• Immunoreceptor tyrosine-based activation motif (ITAM) on CD3ζ
• SH2-binding phosphotyrosine on CTLA-4
• Death domain on Fas

Correct Answer: Immunoreceptor tyrosine-based activation motif (ITAM) on CD3ζ

Q12. Which lymphoid organ is the primary site for B cell affinity maturation and is organized into dark and light zones?

• Bone marrow
• Thymus
• Spleen white pulp marginal zone
• Germinal center within secondary lymphoid follicles

Correct Answer: Germinal center within secondary lymphoid follicles

Q13. Which mechanism best explains how regulatory T cells (Tregs) suppress immune responses?

• Secretion of perforin and granzyme to kill effector T cells
• Production of anti-inflammatory cytokines such as IL-10 and TGF-β
• Upregulation of co-stimulatory molecules on APCs
• Enhancement of Th17 differentiation

Correct Answer: Production of anti-inflammatory cytokines such as IL-10 and TGF-β

Q14. Which event is most directly responsible for immunological memory formation after a primary antigen exposure?

• Immediate IgM secretion by naïve B cells
• Generation of long-lived plasma cells and memory B and T cells
• Activation of complement C5–C9 membrane attack complex
• Upregulation of innate pattern recognition receptors

Correct Answer: Generation of long-lived plasma cells and memory B and T cells

Q15. Which cell-surface molecule provides the critical second signal (co-stimulation) from antigen-presenting cells to naïve T cells via CD28?

• PD-L1
• B7 molecules (CD80/CD86)
• MHC class I
• ICAM-1

Correct Answer: B7 molecules (CD80/CD86)

Q16. Which anatomical compartment of the spleen primarily filters blood-borne pathogens and contains macrophages that remove opsonized bacteria?

• Periarteriolar lymphoid sheath (PALS)
• Follicles in white pulp
• Red pulp
• Trabecular sinus

Correct Answer: Red pulp

Q17. Which immunoglobulin isotype predominantly mediates mucosal immunity and is actively transported across epithelial surfaces via the poly-Ig receptor?

• Serum IgG
• Secretory IgA (dimeric IgA)
• IgM pentamer
• IgD

Correct Answer: Secretory IgA (dimeric IgA)

Q18. Which of the following best describes “cross-presentation” by dendritic cells?

• Presentation of exogenous antigen on MHC class II to CD4+ T cells
• Presentation of exogenous antigen on MHC class I to CD8+ T cells
• Presentation of self-antigen to tolerize B cells
• Presentation of peptide by follicular dendritic cells to B cells

Correct Answer: Presentation of exogenous antigen on MHC class I to CD8+ T cells

Q19. Which genetic loci encode the set of molecules responsible for peptide presentation and are highly polymorphic in humans?

• Immunoglobulin heavy-chain locus
• Major histocompatibility complex (HLA) genes
• Toll-like receptor gene cluster
• Natural killer cell receptor genes

Correct Answer: Major histocompatibility complex (HLA) genes

Q20. Which hypersensitivity type is primarily mediated by immune complex deposition and complement activation, often causing vasculitis and glomerulonephritis?

• Type I (IgE-mediated)
• Type II (antibody-mediated cellular cytotoxicity)
• Type III (immune complex-mediated)
• Type IV (T cell-mediated delayed)

Correct Answer: Type III (immune complex-mediated)

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