T Cell Development

Where does early thymocyte development primarily occur?

What is the primary role of the thymus in T-cell development?

In the thymus, where do T-cell precursors initially begin their development?

Which of the following cell types expresses both CD4 and CD8?

What is the significance of positive selection in T-cell development?

What is the primary outcome of negative selection in T-cell development?

Which process leads to the death of most thymocytes during T-cell development?

What is the ultimate fate of T cells that survive selection in the thymus?

What is the role of the Notch receptor in T-cell development?

In which double negative (DN) stage does TCR rearrangement begin?

Which type of T cell is produced as a result of TCR gene recombination in the DN stages?

What is the significance of β-selection during T-cell development?

Which event is triggered by signals generated after the pre-TCR complex is formed?

What is the outcome of positive selection of a T cell with intermediate affinity for self-MHC molecules?

What is the primary mechanism by which negative selection ensures self-tolerance?

Which event characterizes clonal arrest as a form of self-tolerance?

What is the primary function of regulatory T cells (TREG) in adaptive immunity?

How does apoptosis differ from necrosis?

Which of the following is a characteristic feature that distinguishes apoptosis from necrosis at the cellular level?

What does the instructive model of lineage commitment in T-cell development propose?

According to the kinetic signaling model, what determines whether a T cell commits to the CD4 lineage?

A researcher is studying T-cell development and observes a population of cells in the thymus that express neither CD4 nor CD8. Which stage of thymocyte development are these cells most likely in?

A researcher introduces a mutation in mice that blocks the expression of MHC class II molecules specifically in the thymus. How would this mutation most likely affect T-cell development?

A scientist discovers a new molecule that, when activated, prevents thymocytes with high affinity for self-antigens from undergoing apoptosis. What is the most likely consequence of aberrant activation of this molecule?

A study reveals that a particular genetic defect results in the failure of pre-TCR formation. Which of the following would be the most direct consequence of this defect?

Which model of T-cell lineage commitment suggests that T cells receiving a continuous signal through the TCR commit to the CD4 lineage, whereas an interrupted signal leads to CD8 lineage commitment?

In a mouse model, researchers discover that thymocytes expressing a specific self-antigen receptor are not deleted in the thymus. However, these T cells are present in the periphery but are unresponsive to stimulation. Which mechanism of self-tolerance is most likely at play?

A research team genetically engineers mice to express a modified version of AIRE (AutoImmune REgulator) with enhanced activity. What would be the most likely immunological consequence of this modification?

A researcher is investigating the role of a novel cytokine in T-cell development. They observe that mice lacking this cytokine have a significantly reduced number of double-positive (DP) thymocytes. Which process is most likely affected by the absence of this cytokine?

A scientist is studying the process of programmed cell death in thymocytes. They discover a novel protein that inhibits the activity of caspases, enzymes essential for apoptosis. Which of the following outcomes would be the most likely consequence of overexpression of this protein in thymocytes?

You are analyzing thymocytes in a mouse model with a mutation affecting the gene encoding the pre-TCRα chain. Flow cytometry analysis reveals a significant reduction in cells transitioning from the DN3 to DN4 stage. Which of the following cellular processes directly relies on a functional pre-TCR complex at this developmental juncture?

Within the thymic microenvironment, specific interactions dictate the survival and selection of developing T cells. A researcher isolates cortical thymic epithelial cells (cTECs) and medullary thymic epithelial cells (mTECs) and performs RNA sequencing to identify unique gene expression profiles. Which of the following gene expression signatures would most accurately differentiate mTECs from cTECs?

A pharmaceutical company is developing a new drug designed to enhance positive selection in the thymus to improve T-cell immunity in elderly individuals. The proposed mechanism involves increasing the affinity of TCR-MHC interactions without triggering negative selection. Which of the following potential side effects should be of greatest concern during preclinical safety testing?