PCB 4233 Immunology Final Exam
Questions With Correct Answers
What ligand determines whether bone marrow stem cells will differentiated in B
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cells or T cells? - CORRECT ANSWER✔✔-Notch, Notch positive cells become T
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cells while Notch negative cells become B cells
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Bone marrow stem cells exposed to Notch will become - CORRECT ANSWER✔✔-T
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cells
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Where are Notch ligands found? - CORRECT ANSWER✔✔-The thymic epithelium
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Which process is responsible for driving CD4 or CD8 expression? - CORRECT
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ANSWER✔✔-Positive selection |
Describe positive selection - CORRECT ANSWER✔✔-MHC is presented to naive T
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cells. T cells which bind well to MHC are positively selected for. If there is weak
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binding, the cell undergoes apoptosis (programmed cell death). If the cell binds
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strongly to MHCII, the cell upregulates ThPOK and downregulates Runx3 to
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become a CD4+ T cell. Otherwise, the cell becomes a CD8+ T cell
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ThPOK+Runx3- - CORRECT ANSWER✔✔-CD4+ T cell | | | | |
ThPOK-Runx3+ - CORRECT ANSWER✔✔-CD8+ T cell | | | | |
,Describe negative selection - CORRECT ANSWER✔✔-If a T cell binds too strongly
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to MHC, the cell undergoes apoptosis
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Why is negative selection important? - CORRECT ANSWER✔✔-It is a measure to
| | | | | | | | | | | |
protect against autoimmunity| |
How does negative selection ensure T cells don't respond inappropriately to
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peptide-MHC complexes not found in the thymus? - CORRECT ANSWER✔✔-AIRE | | | | | | | | | |
is a protein that induces expression of proteins not found in the thymus, ex. lung
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protein, to ensure that T cells do not react to proteins found throughout the body
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|after undergoing negative selection
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How do T cells move through the thymus? - CORRECT ANSWER✔✔-1. Arrive to
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thymus via corticomedullary junction
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2. Differentiate into T cells in thymic epithelium
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3. Move into thymic cortex where they proliferate and express TCR
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4. Selection process
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5. Move to thymic medulla
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6. Leave via corticomedullary junction
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What is the role of Bcl-2? - CORRECT ANSWER✔✔-Prevents apoptosis by
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inhibiting Bax and Bak | | |
What is the function of Bax and Bak? - CORRECT ANSWER✔✔-Open
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mitochondrial membrane, releasing cytochrome C, triggering apoptosis | | | | | |
, What is the function of Fas? - CORRECT ANSWER✔✔-Induces apoptosis
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How does the signal from an antigen influence T cell survival? - CORRECT
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ANSWER✔✔-Antigen signal prevents apoptosis by upregulating Bcl-2, without a
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signal from antigen, T cells downregulate Bcl-2, leading to apoptosis as a
| | | | | | | | | | | |
protection measure against autoimmunity
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Where do lymphocytes reach maturity? - CORRECT ANSWER✔✔-Primary organs
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ex. bone marrow, thymus
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Where do mature lymphocytes interact with antigen? - CORRECT ANSWER✔✔-
| | | | | | | | |
Secondary organs |
ex. lymph nodes, spleen, tonsils
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What does the cortex of the thymus contain? - CORRECT ANSWER✔✔-immature
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T-lymphocytes
What does the medulla of the thymus contain? - CORRECT ANSWER✔✔-mature
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T-lymphocytes that are immunocompetent (passed negative selection)
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What is the purpose of lymph? - CORRECT ANSWER✔✔-To carry lymphocytes and
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antigens from body to lymphoid tissues where lymphocytes can recognize
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antigen and become activated
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Questions With Correct Answers
What ligand determines whether bone marrow stem cells will differentiated in B
| | | | | | | | | | | |
cells or T cells? - CORRECT ANSWER✔✔-Notch, Notch positive cells become T
| | | | | | | | | | | |
cells while Notch negative cells become B cells
| | | | | | |
Bone marrow stem cells exposed to Notch will become - CORRECT ANSWER✔✔-T
| | | | | | | | | | |
cells
|
Where are Notch ligands found? - CORRECT ANSWER✔✔-The thymic epithelium
| | | | | | | | |
Which process is responsible for driving CD4 or CD8 expression? - CORRECT
| | | | | | | | | | | |
ANSWER✔✔-Positive selection |
Describe positive selection - CORRECT ANSWER✔✔-MHC is presented to naive T
| | | | | | | | | | |
cells. T cells which bind well to MHC are positively selected for. If there is weak
| | | | | | | | | | | | | | | |
binding, the cell undergoes apoptosis (programmed cell death). If the cell binds
| | | | | | | | | | | |
strongly to MHCII, the cell upregulates ThPOK and downregulates Runx3 to
| | | | | | | | | | |
become a CD4+ T cell. Otherwise, the cell becomes a CD8+ T cell
| | | | | | | | | | | |
ThPOK+Runx3- - CORRECT ANSWER✔✔-CD4+ T cell | | | | |
ThPOK-Runx3+ - CORRECT ANSWER✔✔-CD8+ T cell | | | | |
,Describe negative selection - CORRECT ANSWER✔✔-If a T cell binds too strongly
| | | | | | | | | | | |
to MHC, the cell undergoes apoptosis
| | | | |
Why is negative selection important? - CORRECT ANSWER✔✔-It is a measure to
| | | | | | | | | | | |
protect against autoimmunity| |
How does negative selection ensure T cells don't respond inappropriately to
| | | | | | | | | | |
peptide-MHC complexes not found in the thymus? - CORRECT ANSWER✔✔-AIRE | | | | | | | | | |
is a protein that induces expression of proteins not found in the thymus, ex. lung
| | | | | | | | | | | | | | |
protein, to ensure that T cells do not react to proteins found throughout the body
| | | | | | | | | | | | | |
|after undergoing negative selection
| | |
How do T cells move through the thymus? - CORRECT ANSWER✔✔-1. Arrive to
| | | | | | | | | | | | |
thymus via corticomedullary junction
| | |
2. Differentiate into T cells in thymic epithelium
| | | | | | |
3. Move into thymic cortex where they proliferate and express TCR
| | | | | | | | | |
4. Selection process
| |
5. Move to thymic medulla
| | | |
6. Leave via corticomedullary junction
| | | |
What is the role of Bcl-2? - CORRECT ANSWER✔✔-Prevents apoptosis by
| | | | | | | | | | |
inhibiting Bax and Bak | | |
What is the function of Bax and Bak? - CORRECT ANSWER✔✔-Open
| | | | | | | | | | |
mitochondrial membrane, releasing cytochrome C, triggering apoptosis | | | | | |
, What is the function of Fas? - CORRECT ANSWER✔✔-Induces apoptosis
| | | | | | | | |
How does the signal from an antigen influence T cell survival? - CORRECT
| | | | | | | | | | | | |
ANSWER✔✔-Antigen signal prevents apoptosis by upregulating Bcl-2, without a
| | | | | | | | |
signal from antigen, T cells downregulate Bcl-2, leading to apoptosis as a
| | | | | | | | | | | |
protection measure against autoimmunity
| | |
Where do lymphocytes reach maturity? - CORRECT ANSWER✔✔-Primary organs
| | | | | | | |
ex. bone marrow, thymus
| | |
Where do mature lymphocytes interact with antigen? - CORRECT ANSWER✔✔-
| | | | | | | | |
Secondary organs |
ex. lymph nodes, spleen, tonsils
| | | |
What does the cortex of the thymus contain? - CORRECT ANSWER✔✔-immature
| | | | | | | | | | |
T-lymphocytes
What does the medulla of the thymus contain? - CORRECT ANSWER✔✔-mature
| | | | | | | | | | |
T-lymphocytes that are immunocompetent (passed negative selection)
| | | | | |
What is the purpose of lymph? - CORRECT ANSWER✔✔-To carry lymphocytes and
| | | | | | | | | | |
antigens from body to lymphoid tissues where lymphocytes can recognize
| | | | | | | | | | |
antigen and become activated
| | |
