Immunology Exam (Ch.5-7)

Default pathway of death

_________ is present on all human hematopoietic stem cells. (Hint: a complement)

The period of time over which a population of cells reduces to half its original size.

TCR genes can make nonproductive or productive rearrangements.

• True

• False

The two copies of the Ig-heavy-chain locus helps to increase the likelihood that a pro-B cell will make a productive heavy-chain gene rearrangement.

• True

• False

How do lymphocytes enter and leave the thymus?

Allelic exclusion is the phenomenon whereby a cell expresses only one of its two copies of a gene.

• True

• False

In healthy individuals, approximately twice as many CD4 T cells than CD8 T cells are present in the peripheral circulation. 

• True

• False

Mature T cells divide into...

• Effector T cells

• Repressor T cells

• Plasma cells

• Post-T cells

• Pre-T cells

____________ are viral genes that cause transformation.

Mature B cells arise when the B-cell receptor becomes capable of generating positive signals upon binding specific antigen.

• True

• False

_________ ________ cells posses a high-affinity, isotype-switched antigen receptor.

A double-negative thymocyte does not express...

• CD4 and CD8

• CD34 and CD21

• CD7 and CD11

• CD14 and CD21

• CD4 and CD9

How does positive and negative selection help in selecting thymocytes?

• Positive selection selects cells that are capable of binding to antigens and negative selection removes cells that bind too strongly to self-antigens.

• Positive selection selects cells that do not bind strongly to antigens and negative selection removes cells that do not bind to self-antigens

• Positive selection selects cells that bind to self-antigens and negative selection removes cells that do not bind to antigens

• Positive selection requires the cell to expend energy while negative selection gains energy

• None of the above

A light chain is needed to combine with a heavy chain in order to go to the surface of the cell in B or T cells.

• True

• False

Terminal differentiation defines the process of plasma cells ceasing to divide and no longer expressing Igs and MHC class II molecules.

• True

• False

Which cells become Cytotoxic T cells?

• T cells that express CD8

• T cells that express CD4

• T cells that express CD32

• T cells that express CD58

• Both a and b

Rearrangement of the light-chain genes occurs in the small pre-B cells.

• True

• False

When a rearrangement is successful in the B-chain gene, what two genes are suppressed? 

• RAG 1 and RAG 2

• RAG 3 and RAG 9

• PTa

• Both a and b

• None of the above

IL-7 is a growth factor that acts on late pro-B and pre-B cells.

• True

• False

T cells with an initial nonproductive a-gene rearrangement are highly likely to be rescued by a subsequent rearrangement.

• True

• False

How many checkpoints must a pre-T cell undergo before it is given a signal to survive and proceed to positive selection?

• 2

• 5

• 9

• 0

• 3

Y:D T cells are indifferent to the peptides presented by MHC molecules and recognize different types of antigen.

• True

• False

Self-tolerant mature B cells do not respond to self antigens.

• True

• False

T-cell tumors mostly correspond to either early or late stages in T-cell development.

• True

• False

Immature B cells arise when the rearrangement of the light chain stops.

• True

• False

Peripheral tolerance is induced to antigens outside the bone marrow that removes circulating B cells reactive against self antigens of tissues other than bone marrow.

• True

• False

What are immature T cells called?

• Thymocytes

• Stromal cells

• Lymphocytes

• Plasma cells

• Cytokines

What complement is a characteristic of a stem cell?

• CD34

• CD7

• CD4

• CD8

• CD24

Which two loci compete with the B locus on a double-negative thymocyte during rearrangement?

• Y and D

• B and a

• Y and a

• D and a

• S and z

Which TCR does not undergo positive and negative selection?

• Y:D TCR

• A:B TCR

• D:a TCR

• Y:B TCR

• L:T TCR

Which recombination-activating genes must be present in order for pro-B cells to rearrange?

• RAG 3 and RAG 8

• RAG 4 and RAG 6

• RAG 2 and RAG 4

• RAG 1 and RAG 2

• Just RAG 2

Cytokine ______ is critical in the development of T-cells.

A double negative thymocyte precursor creates:

• A:B and y:D T cells

• A:B and y:G T cells

• L:a and Z:y T cells

• All of the above

• None of the above

Double-positive thymocytes express.....

• Both CD4 and CD8 and a functional receptor

• CD4 and a functional receptor

• CD8 and CD4 with a nonfunctional receptor

• CD34

• CD58 and a functional receptor

The thymic cortical epithelium expresses...

• MHC 1 molecules

• MHC 2 molecules

• Both a and b

• CD12

• None of the above

________ _______ _________ is characterized by a lack of expression of either MHC class I or II molecules by lymphocytes and thymic epithelial cells. (Hint: a syndrome)

The thymic stroma houses what kinds of cells?

• Thymocytes

• B cells

• Plasma cells

• Double-negative thymocytes

• Double-positive thymocytes

How many days does a MHC complex have to be bind to a pre-T-cell in oder to mature further?

• 3-4

• 7-10

• 12-18

• 1-3

• 19-21

What do Regulatory CD4 T cells suppress?

• CD4 self-reactive T cells

• CD8 self-reactive T cells

• AIRE gene mutation

• RAG 1 gene

• RAG 2 gene

Dendritic cells secrete

• CCL21

• CCL19

• Both a and b

• CCL7

• CCL9

Repeated attempts at a-chain gene rearrangement are not possible.

• True

• False

Receptor editing of B cells occurs in 

• Blood

• Thymus

• Bone marrow

• Red marrow

• Yellow pulp

Rearrangement of double-negative thymocytes begins with...

• Rearrangement at the y, D, and B loci at the same time

• Rearrangement at the y, D, and B loci at a different time

• Rearrangement at the a, B, and y loci at the same time

• Rearrangement at the D, S, and y loci at the same time

• Rearrangement at the a, B, and D loci at the same time

Thymocytes that pass a test in which the B-chain is tested for the potential to bind to a-chains are called... 

• Pre-T-cells

• Plasma cells

• Follicular cells

• Lymphatic cells

• Post-T-cells

Why are RAG 1 and RAG 2 suppressed when a successful B-chain of a thymocyte is created?

• So that only one productive B-chain is expressed

• To allow y:D chains to be created

• In order to stop rearrangement in the a-chain

• To signal apoptosis

• RAG 1 and RAG 2 do not get suppressed

Which interleukin stimulates further progression of a B cell in the bone marrow?

• IL-9

• IL-17

• IL-5

• IL-7

• IL-13

 In what syndrome does the thymus fail to develop?

• DiGeroge's syndrome

• Bare lymphocyte syndrome

• Follicular center cell lymphoma

• Hodgkin's Disease

• Lupus