T-cell maturation and differentiation MCQs With Answer

T-cell maturation and differentiation MCQs With Answer

This quiz set is tailored for M.Pharm students to deepen understanding of T‑cell development, lineage commitment, selection processes, and peripheral differentiation. Questions cover thymic architecture, DN/DP/SP stages, pre‑TCR checkpoints, Notch signaling, positive and negative selection, AIRE‑mediated central tolerance, and CD4/CD8 fate decisions. Peripheral subset polarization (Th1/Th2/Th17/Tfh/Treg), transcriptional regulators (T‑bet, GATA3, RORγt, Bcl‑6, Foxp3), co‑stimulation, immune checkpoints, metabolic control, and memory T‑cell phenotypes are also examined. Each multiple‑choice question includes concise distractors and a clear correct answer to support exam preparation and conceptual mastery in immunotechnology.

Q1. Which thymic region is primarily responsible for positive selection of developing thymocytes?

• Thymic medulla mediated by medullary thymic epithelial cells (mTECs)
• Thymic cortex mediated by cortical thymic epithelial cells (cTECs)
• Perivascular space near the corticomedullary junction
• Bone marrow stromal compartment

Correct Answer: Thymic cortex mediated by cortical thymic epithelial cells (cTECs)

Q2. Which sequence correctly describes the early double‑negative (DN) stages of αβ T‑cell development and where β‑selection occurs?

• DN1 → DN2 → DN3 → DN4; β‑selection at DN3
• DN1 → DN2 → DN4 → DN3; β‑selection at DN4
• DN4 → DN3 → DN2 → DN1; β‑selection at DN2
• DN2 → DN1 → DN3 → DN4; β‑selection at DN1

Correct Answer: DN1 → DN2 → DN3 → DN4; β‑selection at DN3

Q3. The pre‑TCR complex that signals successful TCRβ rearrangement consists of which components?

• TCRα chain paired with CD3 complex
• TCRβ chain paired with pre‑Tα (pTα) and CD3 complex
• γδ TCR chains associated with CD8
• MHC class II bound self‑peptide and CD4

Correct Answer: TCRβ chain paired with pre‑Tα (pTα) and CD3 complex

Q4. Which signaling pathway is essential for committing lymphoid progenitors in the thymus to the T‑cell lineage?

• Wnt/β‑catenin signaling
• Notch1 signaling
• Hedgehog signaling
• TGF‑β/SMAD signaling

Correct Answer: Notch1 signaling

Q5. MHC restriction of T‑cell recognition means:

• T cells recognize intact pathogens without antigen processing
• T cells recognize peptide antigens only when presented by self‑MHC molecules
• T cells can recognize peptide on any species’ MHC molecule equally
• T cells bind free soluble peptides in plasma

Correct Answer: T cells recognize peptide antigens only when presented by self‑MHC molecules

Q6. The transcription factors primarily directing CD4 versus CD8 lineage fate are:

• Runx3 promotes CD4 fate; ThPOK promotes CD8 fate
• ThPOK promotes CD4 fate; Runx3 promotes CD8 fate
• GATA3 promotes CD8 fate; T‑bet promotes CD4 fate
• Foxp3 promotes CD4 fate; RORγt promotes CD8 fate

Correct Answer: ThPOK promotes CD4 fate; Runx3 promotes CD8 fate

Q7. AIRE expression in medullary thymic epithelial cells is important for:

• Positive selection of low‑affinity thymocytes
• Expression of tissue‑restricted antigens for central tolerance and deletion of autoreactive T cells
• Induction of Notch signaling in early thymocytes
• Peripheral activation of mature T cells in lymph nodes

Correct Answer: Expression of tissue‑restricted antigens for central tolerance and deletion of autoreactive T cells

Q8. Differentiation of naïve CD4+ T cells into Th1 cells is primarily driven by which cytokine and transcription factor?

• IL‑4 and GATA3
• IL‑6 and RORγt
• IL‑12 and T‑bet
• TGF‑β and Foxp3

Correct Answer: IL‑12 and T‑bet

Q9. Which cytokine and master regulator pair drives Th2 differentiation?

• IL‑12 and T‑bet
• IL‑4 and GATA3
• IL‑6 and Bcl‑6
• IL‑21 and RORγt

Correct Answer: IL‑4 and GATA3

Q10. Th17 cell differentiation from naïve CD4+ T cells is promoted by which combination?

• IL‑2 alone with Foxp3 induction
• TGF‑β + IL‑6 with RORγt as the transcription factor
• IL‑12 + IFN‑γ with T‑bet induction
• IL‑4 + IL‑5 with GATA3 induction

Correct Answer: TGF‑β + IL‑6 with RORγt as the transcription factor

Q11. Induced peripheral regulatory T cells (iTregs) require which factors for differentiation and which transcription factor defines them?

• IL‑6 + IL‑23 and transcription factor RORγt
• TGF‑β + IL‑2 and transcription factor Foxp3
• IL‑12 + IL‑18 and transcription factor T‑bet
• IL‑4 + IL‑13 and transcription factor GATA3

Correct Answer: TGF‑β + IL‑2 and transcription factor Foxp3

Q12. T follicular helper (Tfh) cell differentiation is characterized by which transcription factor and chemokine receptor?

• GATA3 and CCR4
• Bcl‑6 and CXCR5
• T‑bet and CXCR3
• Foxp3 and CCR7

Correct Answer: Bcl‑6 and CXCR5

Q13. Which phenotype correctly identifies central memory (Tcm) versus effector memory (Tem) CD8+ T cells?

• Tcm: CCR7– CD62L–; Tem: CCR7+ CD62L+
• Tcm: CCR7+ CD62L+; Tem: CCR7– CD62L–
• Tcm: PD‑1+ TIM‑3+; Tem: Bcl‑2 high
• Tcm: high granzyme B; Tem: high IL‑7Rα (CD127)

Correct Answer: Tcm: CCR7+ CD62L+; Tem: CCR7– CD62L–

Q14. Survival and homeostasis of naïve T cells in the periphery critically depend on which cytokine and mechanism?

• IL‑4 signaling and constant antigen stimulation
• IL‑7 signaling and low‑affinity self‑peptide/MHC interactions maintaining Bcl‑2 expression
• High‑affinity foreign antigen recognition and IL‑15
• TGF‑β signaling and upregulation of RORγt

Correct Answer: IL‑7 signaling and low‑affinity self‑peptide/MHC interactions maintaining Bcl‑2 expression

Q15. PD‑1 and CTLA‑4 expressed on activated T cells primarily function to:

• Enhance TCR signaling and IL‑2 secretion
• Serve as chemokine receptors for lymph node homing
• Act as inhibitory immune checkpoints that limit T‑cell activation
• Promote class switching in B cells

Correct Answer: Act as inhibitory immune checkpoints that limit T‑cell activation

Q16. Negative selection in the thymus leads to which cellular outcome for high‑affinity self‑reactive thymocytes?

• Positive selection into the peripheral naïve pool
• Differentiation into γδ T cells
• Apoptotic deletion mediated by intrinsic apoptotic pathways (e.g., Bim)
• Immediate conversion into regulatory B cells

Correct Answer: Apoptotic deletion mediated by intrinsic apoptotic pathways (e.g., Bim)

Q17. γδ T cells differ from conventional αβ T cells in that they:

• Require MHC class II for antigen recognition
• Develop exclusively in peripheral lymph nodes
• Often recognize antigens in an MHC‑independent manner and localize to epithelial tissues
• Always express CD4 or CD8 coreceptors

Correct Answer: Often recognize antigens in an MHC‑independent manner and localize to epithelial tissues

Q18. The “β‑selection” checkpoint in thymocyte development tests for:

• Successful TCRα rearrangement and positive selection
• Productive TCRβ rearrangement allowing proliferation and transition to the double‑positive stage
• Expression of CD4 versus CD8 lineage markers
• Exit competence for peripheral homing

Correct Answer: Productive TCRβ rearrangement allowing proliferation and transition to the double‑positive stage

Q19. How does mTOR signaling influence T‑cell fate decisions?

• mTOR activity favors regulatory T‑cell development and lipid oxidation
• mTOR activation promotes effector T‑cell differentiation and glycolytic metabolism; inhibition (rapamycin) favors memory/Treg development
• mTOR exclusively controls B‑cell isotype switching
• mTOR inhibition increases glycolysis and effector differentiation

Correct Answer: mTOR activation promotes effector T‑cell differentiation and glycolytic metabolism; inhibition (rapamycin) favors memory/Treg development

Q20. Co‑stimulation via CD28 binding to B7 molecules on antigen‑presenting cells is required because:

• It directly presents antigenic peptide to the TCR
• It prevents anergy, enhances IL‑2 production, and supports full T‑cell activation
• It mediates negative selection within the thymus
• It is only required for γδ T‑cell activation

Correct Answer: It prevents anergy, enhances IL‑2 production, and supports full T‑cell activation

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