Section 5.7 Quiz

* not completed

. 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.

double-negative thymocytes correct incorrect

natural killer cells correct incorrect

macrophages correct incorrect

cortical thymic epithelial cells correct incorrect

* not completed

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

The secretion of the RAG1 and RAG2 proteins correct incorrect

The ability to express both CD4 and CD8 coreceptors correct incorrect

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

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

* not completed

. 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

* not completed

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

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

They remove thymocytes that lack functional coreceptors. correct incorrect

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