Section 5.7 Quiz

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. Double-positive (DP) thymocytes that have passed the checkpoints that occur during somatic recombination are tested by antigen-presenting cells (APCs) or _____ for the affinity of their T-cell receptor for MHC class I or II molecules presenting antigen.

macrophages correct incorrect

natural killer cells correct incorrect

cortical thymic epithelial cells correct incorrect

double-negative thymocytes correct incorrect

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. Which of the following forms the basis of the selection process of thymocytes within the thymic cortex?

The ability to interact with an MHC class I molecule rather than an MHC class II molecule correct incorrect

The ability to express both CD4 and CD8 coreceptors correct incorrect

The affinity of the T-cell receptor for the MHC–peptide complexes correct incorrect

The secretion of the RAG1 and RAG2 proteins correct incorrect

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. Most cells that have passed through the α and βcheckpoints undergo positive selection and are circulated in the body.

True correct incorrect

False correct incorrect

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. Identify a true statement about the role of dendritic cells in T-cell development.

They allow for positive selection of CD4+ thymocytes that bear a T-cell receptor that interacts too strongly with MHC molecules. correct incorrect

They remove thymocytes that lack functional coreceptors. correct incorrect

They present tissue-specific antigens via MHC class II antigen presentation. correct incorrect

They are completely responsible for the negative selection of CD8+ thymocytes within the thymic medulla. correct incorrect