TCR Gene Rearrangement and Organization

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What is the configuration of the TCR genes in the earliest cell entering the thymus?

Unrearranged

Partially rearranged

Completely rearranged

Rearranged (correct)

What is the order of gene rearrangement if the γ chain genes rearrange successfully?

α gene rearrangement then δ chain genes

β gene rearrangement then δ chain genes

δ chain genes then α gene rearrangement

δ chain genes then β gene rearrangement (correct)

What is the role of recombination activation genes (RAGs) in T cells?

To generate TCR diversity

To inhibit the recombinase gene

To activate the recombinase gene (correct)

To regulate the allelic exclusion

What is the approximate number of different TCR structures that can be generated from αβ and γδ TCRs?

10^13 Signup and view all the answers

What is the process called when no further gene rearrangements occur after successful gene rearrangements?

Allelic exclusion Signup and view all the answers

What happens if all the gene rearrangements are unsuccessful?

The second copy of genes on respective chromosomes will begin the rearrangement process Signup and view all the answers

What is the function of RAG-1 and RAG-2 genes in the process of recombination?

To recognize specific DNA signal sequences Signup and view all the answers

What is the difference between immuneoglobulin genes and genes encoding TCR?

Immunoglobulin genes do not undergo somatic mutation Signup and view all the answers

Where do T lymphocytes develop?

In the thymus Signup and view all the answers

What is the function of positive selection in the thymus?

To allow TCRs to recognize MHC molecules Signup and view all the answers

What is the outcome of TCRs binding too strongly to p-MHC in the thymus?

Negative selection and elimination Signup and view all the answers

What is the outcome of a defect in RAG-1 or RAG-2 genes?

Severe combined immunodeficiency (SCID) Signup and view all the answers

What is the name of the cells that do not express either the CD4 or CD8 co-receptor?

Double-negative cells Signup and view all the answers

At what stage do the cells decide to become δγ or αβ T cells?

At the double-negative stage Signup and view all the answers

What percentage of thymocytes never become fully functional and die in the thymus?

96%-98% Signup and view all the answers

What is the result of positive selection?

Down-regulation of RAG1 and RAG2 gene expression Signup and view all the answers

What is the function of negative selection?

To remove T cells that express TCR with high reactivity to self components Signup and view all the answers

What type of molecule is associated with the TCR β chain on the surface of pre-T cells?

Invariant pre-Tα molecule Signup and view all the answers

What type of T-cells are MHC II restricted and recognize specific foreign peptides only when presented in association with specific MHC II molecules?

CD4 T-cells Signup and view all the answers

Which type of T-cells produces cytokines of CMI and inflammation?

Th1 T-cells Signup and view all the answers

What is the primary function of CD4 T-cells when recognizing antigen on the surface of APC?

Secreting cytokines Signup and view all the answers

What is the term for the process by which T-cells that are unable to bind to MHC molecules are eliminated?

Negative selection Signup and view all the answers

What is the primary function of CD8 T-cells?

Killing infected cells Signup and view all the answers

What is the term for immature T-cells that express both CD4 and CD8?

Double-positive T-cells Signup and view all the answers

What is the result of pre-TCR signaling in the development of cells expressing α and β as their TCR?

Further rearrangement of TCR β genes stops Signup and view all the answers

What is the main function of positive selection in thymic selection?

Recognition of self-MHC and self-peptide Signup and view all the answers

What is the composition of the pre-T cell receptor (pre-TCR)?

β chain and pre-Tα Signup and view all the answers