PASSPOINT PRO
BIOL 3201
IMMUNOLOGY
Quiz 6 Practice
Development & Activation of T Cells
EXPLAINED
70 QUESTIONS A-D FORMAT
Answer + rationale after each
Focused quiz-style practice Pathway + scenario MCQs
item
Core coverage: thymocyte stages, beta-selection, positive and negative selection, central
tolerance, AIRE, CD4/CD8 lineage commitment, T-cell activation signals, costimulation, IL-2
and clonal expansion, helper T-cell differentiation, CTL killing, immune regulation,
contraction, and memory.
,BIOL 3201 IMMUNOLOGY - QUIZ 6 PRACTICE
Quiz 6 Focus
This practice set targets Module 6: Development and Activation of T Cells. Questions emphasize developmental
checkpoints, tolerance, activation requirements, helper-subset differentiation, cytotoxic mechanisms, and
scenario-based reasoning. The goal is to practice the sequence of events and the consequences of changing one
signal, receptor, or selection step.
01 Where do most conventional alpha-beta T cells complete their development?
A. In the thymus
B. In bone marrow follicles
C. In the splenic red pulp
D. In the liver sinusoids after adulthood
Answer: A
Explanation: Developing T-cell precursors arise from hematopoietic progenitors but complete most conventional alpha-beta T-cell
development in the thymus. The thymic environment provides signals for receptor rearrangement and selection. Mature naive T cells then
leave for secondary lymphoid tissues.
02 An early thymocyte that lacks surface CD4 and CD8 is described as:
A. Double positive
B. Single positive
C. Double negative
D. Terminally differentiated
Answer: C
Explanation: The earliest thymocyte stages are CD4-negative and CD8-negative and are therefore called double negative. Later cells
commonly express both coreceptors as double-positive thymocytes. Selection then yields mainly single-positive CD4 or CD8 cells.
03 What is the major purpose of beta-selection during T-cell development?
A. To test whether the mature TCR binds soluble antibody
B. To induce class switching of the TCR
C. To select only cells that cannot signal through CD3
D. To test whether a productive TCR beta chain can form a functional pre-TCR
Answer: D
Explanation: Beta-selection checks whether TCR beta-chain rearrangement has succeeded. A productive beta chain pairs with pre-T
alpha and signaling components to form the pre-TCR. Successful signaling promotes survival, proliferation, and progression toward the
double-positive stage.
04 A thymocyte fails to make a productive TCR beta-chain rearrangement on either allele. What is the most
likely outcome?
A. It immediately becomes a mature CD8 T cell
B. It switches to antibody production
C. It fails beta-selection and usually dies
D. It exits the thymus as a naive B cell
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, BIOL 3201 IMMUNOLOGY - QUIZ 6 PRACTICE
Answer: C
Explanation: Without a functional beta chain, a conventional alpha-beta thymocyte cannot assemble a signaling pre-TCR. It therefore
fails beta-selection and does not receive the survival and proliferative signals needed to continue normal development.
05 A typical double-positive thymocyte expresses:
A. Neither CD4 nor CD8
B. Only CD19 and CD21
C. Only CD16 and CD56
D. Both CD4 and CD8
Answer: D
Explanation: Double-positive thymocytes coexpress CD4 and CD8. This stage is important because the newly formed alpha-beta TCR
can be tested against self peptide-MHC complexes. The outcome of selection helps determine survival and coreceptor lineage.
06 Positive selection primarily ensures that developing alpha-beta T cells:
A. Bind self antigens as strongly as possible
B. Ignore MHC molecules completely
C. Can recognize self MHC molecules with an appropriate low-to-moderate affinity
D. Recognize only free soluble proteins
Answer: C
Explanation: Positive selection preserves thymocytes whose TCRs can interact usefully with self MHC. Cells that cannot recognize self
MHC receive inadequate survival signals and die by neglect. This creates the basis of MHC restriction.
07 Positive selection of conventional T cells occurs mainly in the:
A. Thymic cortex
B. Bone marrow medulla
C. Splenic red pulp
D. Lymph-node medullary cords only
Answer: A
Explanation: Cortical thymic epithelial cells are central participants in positive selection. They present self peptide-MHC complexes to
double-positive thymocytes. Cells able to interact appropriately can survive and continue maturation.
08 A double-positive thymocyte cannot recognize either self MHC class I or class II. What is the most likely
fate?
A. Clonal expansion into an effector cell
B. Immediate differentiation into a plasma cell
C. Death by neglect
D. Class switching from CD4 to CD8
Answer: C
Explanation: A thymocyte must receive a sufficient survival signal through recognition of self peptide-MHC during positive selection.
Cells whose TCRs fail to recognize self MHC generally die by neglect. This removes receptors that would be ineffective in the host MHC
environment.
09 During positive selection, recognition of MHC class I most strongly favors development toward the:
A. CD4 single-positive lineage
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BIOL 3201
IMMUNOLOGY
Quiz 6 Practice
Development & Activation of T Cells
EXPLAINED
70 QUESTIONS A-D FORMAT
Answer + rationale after each
Focused quiz-style practice Pathway + scenario MCQs
item
Core coverage: thymocyte stages, beta-selection, positive and negative selection, central
tolerance, AIRE, CD4/CD8 lineage commitment, T-cell activation signals, costimulation, IL-2
and clonal expansion, helper T-cell differentiation, CTL killing, immune regulation,
contraction, and memory.
,BIOL 3201 IMMUNOLOGY - QUIZ 6 PRACTICE
Quiz 6 Focus
This practice set targets Module 6: Development and Activation of T Cells. Questions emphasize developmental
checkpoints, tolerance, activation requirements, helper-subset differentiation, cytotoxic mechanisms, and
scenario-based reasoning. The goal is to practice the sequence of events and the consequences of changing one
signal, receptor, or selection step.
01 Where do most conventional alpha-beta T cells complete their development?
A. In the thymus
B. In bone marrow follicles
C. In the splenic red pulp
D. In the liver sinusoids after adulthood
Answer: A
Explanation: Developing T-cell precursors arise from hematopoietic progenitors but complete most conventional alpha-beta T-cell
development in the thymus. The thymic environment provides signals for receptor rearrangement and selection. Mature naive T cells then
leave for secondary lymphoid tissues.
02 An early thymocyte that lacks surface CD4 and CD8 is described as:
A. Double positive
B. Single positive
C. Double negative
D. Terminally differentiated
Answer: C
Explanation: The earliest thymocyte stages are CD4-negative and CD8-negative and are therefore called double negative. Later cells
commonly express both coreceptors as double-positive thymocytes. Selection then yields mainly single-positive CD4 or CD8 cells.
03 What is the major purpose of beta-selection during T-cell development?
A. To test whether the mature TCR binds soluble antibody
B. To induce class switching of the TCR
C. To select only cells that cannot signal through CD3
D. To test whether a productive TCR beta chain can form a functional pre-TCR
Answer: D
Explanation: Beta-selection checks whether TCR beta-chain rearrangement has succeeded. A productive beta chain pairs with pre-T
alpha and signaling components to form the pre-TCR. Successful signaling promotes survival, proliferation, and progression toward the
double-positive stage.
04 A thymocyte fails to make a productive TCR beta-chain rearrangement on either allele. What is the most
likely outcome?
A. It immediately becomes a mature CD8 T cell
B. It switches to antibody production
C. It fails beta-selection and usually dies
D. It exits the thymus as a naive B cell
PassPoint Pro | Focus: Development and Activation of T Cells Page 2
, BIOL 3201 IMMUNOLOGY - QUIZ 6 PRACTICE
Answer: C
Explanation: Without a functional beta chain, a conventional alpha-beta thymocyte cannot assemble a signaling pre-TCR. It therefore
fails beta-selection and does not receive the survival and proliferative signals needed to continue normal development.
05 A typical double-positive thymocyte expresses:
A. Neither CD4 nor CD8
B. Only CD19 and CD21
C. Only CD16 and CD56
D. Both CD4 and CD8
Answer: D
Explanation: Double-positive thymocytes coexpress CD4 and CD8. This stage is important because the newly formed alpha-beta TCR
can be tested against self peptide-MHC complexes. The outcome of selection helps determine survival and coreceptor lineage.
06 Positive selection primarily ensures that developing alpha-beta T cells:
A. Bind self antigens as strongly as possible
B. Ignore MHC molecules completely
C. Can recognize self MHC molecules with an appropriate low-to-moderate affinity
D. Recognize only free soluble proteins
Answer: C
Explanation: Positive selection preserves thymocytes whose TCRs can interact usefully with self MHC. Cells that cannot recognize self
MHC receive inadequate survival signals and die by neglect. This creates the basis of MHC restriction.
07 Positive selection of conventional T cells occurs mainly in the:
A. Thymic cortex
B. Bone marrow medulla
C. Splenic red pulp
D. Lymph-node medullary cords only
Answer: A
Explanation: Cortical thymic epithelial cells are central participants in positive selection. They present self peptide-MHC complexes to
double-positive thymocytes. Cells able to interact appropriately can survive and continue maturation.
08 A double-positive thymocyte cannot recognize either self MHC class I or class II. What is the most likely
fate?
A. Clonal expansion into an effector cell
B. Immediate differentiation into a plasma cell
C. Death by neglect
D. Class switching from CD4 to CD8
Answer: C
Explanation: A thymocyte must receive a sufficient survival signal through recognition of self peptide-MHC during positive selection.
Cells whose TCRs fail to recognize self MHC generally die by neglect. This removes receptors that would be ineffective in the host MHC
environment.
09 During positive selection, recognition of MHC class I most strongly favors development toward the:
A. CD4 single-positive lineage
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