lecture 13 multiple chocie quiz- immunology

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What is one of the key differences between B and T lymphocytes in terms of their maturation process?

B lymphocytes undergo selection and elimination of cells that strongly recognize self antigens.

B lymphocytes undergo recombination of antigen receptor chains.

T lymphocytes differentiate into distinct subpopulations. (correct)

T lymphocytes go through a proliferation phase once committed to the lineage.

Which process occurs in both B and T lymphocyte maturation?

Sequential rearrangement (recombination) of antigen receptor chains.

Selection of cells expressing functional antigen receptors.

Proliferation of progenitor cells and immature committed cells. (correct)

Differentiation of B and T cells into distinct subpopulations.

What is the main purpose of lymphocyte maturation?

To develop autoimmune responses

To ensure the generation of diverse, functional lymphocytes capable of recognizing pathogens (correct)

To prevent the generation of functional lymphocytes

To promote the differentiation of B and T cells into identical subpopulations

During lymphocyte maturation, what is the purpose of the selection process involving functional antigen receptors?

To eliminate cells that strongly recognize self antigens. Signup and view all the answers

Which event is a crucial checkpoint in B cell maturation?

Selection and elimination of self-reactive cells. Signup and view all the answers

What happens to cells that fail to meet requirements at the checkpoints during maturation?

They undergo apoptosis Signup and view all the answers

What is the purpose of the first checkpoint in cell maturation?

To assess if the first chain is functional Signup and view all the answers

What drives the commitment of progenitor cells to either the B or T cell lineage during lymphocyte maturation?

Specific transcription factors and signaling pathways. Signup and view all the answers

What happens if a cell only makes one polypeptide chain during receptor assembly?

It undergoes apoptosis Signup and view all the answers

What are the specific functions of differentiated B cells?

Produce antibodies Signup and view all the answers

What is the role of receptor editing in B cells?

Refine the B cell repertoire and promote self-tolerance Signup and view all the answers

How does positive selection impact lymphocyte survival?

Promotes the survival of lymphocytes with weak interactions with self-antigens Signup and view all the answers

What do the two rounds of sequential rearrangement in B cell maturation involve?

Assembly of V, D, and J gene segments for heavy chains Signup and view all the answers

What contributes to the establishment of a functional and self-tolerant immune system?

Negative selection Signup and view all the answers

What is the function of pre-B cell receptor in B cell development?

Ensures functional testing of B cell receptors Signup and view all the answers

What is the purpose of positive selection in the context of lymphocyte maturation?

Promotes survival of lymphocytes with weak interactions with self antigens Signup and view all the answers

Which process occurs during negative selection in lymphocyte maturation?

Promotes clonal deletion of T cells binding strongly to self antigens Signup and view all the answers

What is the purpose of allelic exclusion in B cell maturation?

To ensure that only one version of the antigen receptor becomes functional Signup and view all the answers

What is the main outcome of clonal deletion in the immune system?

Eliminates T cells binding strongly to self antigens Signup and view all the answers

What is a key role of the pre-BCR in B cell maturation?

Promoting allelic exclusion Signup and view all the answers

Why is positive selection important in maintaining the integrity of the immune system?

To ensure the survival of lymphocytes with weak interactions with self antigens Signup and view all the answers

In T cell maturation, what occurs during sequential rearrangement?

One TCR gene is rearranged at a time Signup and view all the answers

Which statement best describes the role of receptor editing in B cell maturation?

Allows B cells to undergo further rearrangements to correct autoimmunity Signup and view all the answers

Why do immature B cells initially express two versions of the antigen receptor?

To increase diversity in antigen recognition Signup and view all the answers

What is a distinct difference between B cell and T cell maturation processes?

Activation by pre-BCR Signup and view all the answers

What role does the pre-TCR play in T cell development?

Promoting proliferation and inhibiting further rearrangement of TCR beta chain genes Signup and view all the answers

Which event marks the completion of the beta-selection checkpoint in T cell development?

Transition from pre-T cell to double-positive (CD4+CD8+) thymocytes Signup and view all the answers

What is the main function of positive selection during T cell development?

Selecting T cells capable of recognizing a wide range of antigens Signup and view all the answers

During T cell development, what happens as a result of the pre-TCR promoting proliferation?

Inhibition of further rearrangement of TCR beta chain genes Signup and view all the answers

What is the key transition that occurs after pro-T cells enter the thymus?

Transition from double-negative to double-positive thymocytes Signup and view all the answers

What is the role of positive selection during T cell maturation in the thymus?

To provide survival signals to thymocytes with TCRs weakly interacting with self-peptide-MHC complexes Signup and view all the answers

What happens to double-positive (CD4+CD8+) thymocytes that fail to pass the selection process in the thymic cortex?

They undergo apoptosis and are eliminated from the maturation process. Signup and view all the answers

Which surface markers are characteristic of double-negative (CD4-CD8-) thymocytes as they progress through maturation stages?

CD44, CD25, and CD117 Signup and view all the answers

What is the main function of double-positive (CD4+CD8+) thymocytes?

To undergo positive selection in the thymic cortex Signup and view all the answers

Which event characterizes the transition from double-negative to double-positive thymocytes?

Expression of a different combination of CD25, CD44, and CD117 surface markers Signup and view all the answers

What happens to T cells with TCRs capable of strongly interacting with self-peptide-MHC complexes during positive selection?

They undergo apoptosis due to self-tolerance mechanisms. Signup and view all the answers

What is a consequence of pre-T cell receptors failing to interact with self-peptide-MHC complexes during maturation?

Apoptosis of thymocytes that do not pass the selection process Signup and view all the answers

Why is positive selection considered a crucial process during T cell maturation?

It allows for the generation of T cells capable of recognizing self-peptides presented by MHC molecules. Signup and view all the answers

What is one of the key functions of double-positive (CD4+CD8+) thymocytes during maturation?

To undergo positive selection in the thymic medulla. Signup and view all the answers

Why do thymocytes progress through stages characterized by changes in surface marker expression during development?

To mark different stages of maturation and identify developmental status. Signup and view all the answers