PCB 3233 Immunology Exam 4 Questions
with Correct Answers| Latest Update
Positive Selection
leads to the death of immature T-cells having receptors that do not interact with any self-MHC I
or II (takes place prior to negative selection)
Negative Selection
induces death of those immature T-cells that are autoreactive (also happens with B-cells)
Majority Lineage Type of T-Cell
a:b (α:β 95%)
Minority Lineage Type of T-Cell
g:d (γ:δ 5%)
What is another word for immature T-cell?
thymocyte
What is the epithelial cell network that thymocytes are embedded in called?
thymic stroma
,What takes place in the Thymus Cortex?
most of T-cell maturation (except negative selection)
What takes place in the Thymus Medulla?
negative selection of T-cells
What do macrophages in the cortex and medulla do?
remove thymocytes that fail to mature properly
What are Hassall's corpuscles?
a feature of the medulla; site of cell destruction
What is DiGeorge syndrome?
deletion of chromosome 22; thymus fails to develop
Progenitor T-Cell
lack the cell surface glycoproteins (have CD34 surface glycoprotein of stem cells), germline
configuration
,Double Negative Thymocyte
at the start of gene rearrangement; no CD4 or CD8
Double Positive Thymocyte
after rearrangement; expresses both CD4 and CD8
Single Positive Thymocyte
after positive selection; expresses CD4 or CD8
IL-7 Receptor
essential for binding IL-7 secreted by thymic stromal cells; helps tell the cell what to do next
Notch-1
at all stages of maturation in the thymus signals are sent to this receptor to drive the T-cell in
their differentiation
How many chances (per chromosome) does the B-chain have to rearrange productivly?
2
, What does a successful rearrangement of the B-chain induce?
expression of CD4 and CD8
Allelic Exclusion of B-chain
proliferation initiated by signaling is repressed
What signals are repressed in allelic exclusion of the B-chain?
pre-TCR, RAG-1, RAG-2
When does rearrangement of the a-chain occur?
after the double-positive cells stop dividing
Will most developing T-cell be able to make a productive a-chain rearrangement?
yes
What happens after the first rearrangement between V and J segments on the a-chain?
d (δ) segment is deleted
What is the first checkpoint of a:b (α:β) chain rearrangement?
with Correct Answers| Latest Update
Positive Selection
leads to the death of immature T-cells having receptors that do not interact with any self-MHC I
or II (takes place prior to negative selection)
Negative Selection
induces death of those immature T-cells that are autoreactive (also happens with B-cells)
Majority Lineage Type of T-Cell
a:b (α:β 95%)
Minority Lineage Type of T-Cell
g:d (γ:δ 5%)
What is another word for immature T-cell?
thymocyte
What is the epithelial cell network that thymocytes are embedded in called?
thymic stroma
,What takes place in the Thymus Cortex?
most of T-cell maturation (except negative selection)
What takes place in the Thymus Medulla?
negative selection of T-cells
What do macrophages in the cortex and medulla do?
remove thymocytes that fail to mature properly
What are Hassall's corpuscles?
a feature of the medulla; site of cell destruction
What is DiGeorge syndrome?
deletion of chromosome 22; thymus fails to develop
Progenitor T-Cell
lack the cell surface glycoproteins (have CD34 surface glycoprotein of stem cells), germline
configuration
,Double Negative Thymocyte
at the start of gene rearrangement; no CD4 or CD8
Double Positive Thymocyte
after rearrangement; expresses both CD4 and CD8
Single Positive Thymocyte
after positive selection; expresses CD4 or CD8
IL-7 Receptor
essential for binding IL-7 secreted by thymic stromal cells; helps tell the cell what to do next
Notch-1
at all stages of maturation in the thymus signals are sent to this receptor to drive the T-cell in
their differentiation
How many chances (per chromosome) does the B-chain have to rearrange productivly?
2
, What does a successful rearrangement of the B-chain induce?
expression of CD4 and CD8
Allelic Exclusion of B-chain
proliferation initiated by signaling is repressed
What signals are repressed in allelic exclusion of the B-chain?
pre-TCR, RAG-1, RAG-2
When does rearrangement of the a-chain occur?
after the double-positive cells stop dividing
Will most developing T-cell be able to make a productive a-chain rearrangement?
yes
What happens after the first rearrangement between V and J segments on the a-chain?
d (δ) segment is deleted
What is the first checkpoint of a:b (α:β) chain rearrangement?
