PCB 3233 IMMUNOLOGY EXAM 4 QUESTIONS &
ANSWERS
Positive Selection - Answer -makes sure that your T-Cell recognizes one of your MHC.
If it does not, then apoptosis
Negative Selection - Answer -Makes sure it does not recognize your peptide:MHC too
strongly
Does gamma: delta T-cells have to go through positive selection? - Answer -No
What does turning off RAG 1&2 do to your gene rearrangement? - Answer -Preserve
the current rearrangement
Primary Lymphoid Tissue - Answer -bone marrow and thymus
What does TH1 cells do? - Answer -Activate macrophages
Thymal Stromal Cells - Answer -Keeps BCR genes closed and opens TCR genes
IgM activates? - Answer -complement
Notch-1 - Answer -The signal for survival. It drives the cell on the T-cell path — signals
to open up T-cell rearrangement.
Signaling rearrangement keeps T-cel on T-cell pathway
Where does Maturation and Positive Selection occur? - Answer -Cortex of the thymus
Can negative selection also take place in the Cortex? - Answer -Yes, negative selection
can take place in the cortex at the same time as positive selection
Where does negative selection take place? - Answer -medulla of thymus
Where are mature thymocytes located? - Answer -Medulla
Where are immature thymocytes located? - Answer -Cortex
What special cells are in the Medulla - Answer -Dendritic cells, macrophages, and
medullary epithelial cells
, What special cells are in the cortex? - Answer -Cortical epithelial cells and
macrophages
Where can you find AIRE? - Answer -in the medullary epithelial cells
AIRE - Answer -Autoimmune regulator
made by medullary epithelial cells
Creates a couple hundred peripheral peptides that can be used to test T-cells for
negative selection
DiGeorge's syndrome - Answer -deletion in chromosome 22 in which thymus fails to
develop and T-cells are absent
Hassall's corpuscles - Answer -macrophages in both cortex and medulla remove the
many thymocytes that fail to mature properly
Involution of the Thymus - Answer -Progressively shrinks, fat gradually claiming areas
once packed with thymocytes
-reduces production of new T-cells
Double negative - Answer -No CD4 and CD8
Double Positive - Answer -CD4 and CD8 are present
Single Positive - Answer -has either CD4 or CD8
CD2 and CD5 - Answer -perform adhesion and signaling. They are present during
double negative stage
Thymocytes rearrange which 3 genes at the same time? - Answer -Beta, gamma, and
delta
pTalpha - Answer -surrogate alpha chain. signals cell to halt gamma, delta, Beta
chains, gene rearrangement and begin proliferation.
What do macrophages do in the thymus? - Answer -continually remove dead cells
How many rearrangements can successfully make a Beta chain? - Answer -up to 4
attempts
d:k light chain can have a minimum of how many rearrangements? - Answer -4
minimum attempts
ANSWERS
Positive Selection - Answer -makes sure that your T-Cell recognizes one of your MHC.
If it does not, then apoptosis
Negative Selection - Answer -Makes sure it does not recognize your peptide:MHC too
strongly
Does gamma: delta T-cells have to go through positive selection? - Answer -No
What does turning off RAG 1&2 do to your gene rearrangement? - Answer -Preserve
the current rearrangement
Primary Lymphoid Tissue - Answer -bone marrow and thymus
What does TH1 cells do? - Answer -Activate macrophages
Thymal Stromal Cells - Answer -Keeps BCR genes closed and opens TCR genes
IgM activates? - Answer -complement
Notch-1 - Answer -The signal for survival. It drives the cell on the T-cell path — signals
to open up T-cell rearrangement.
Signaling rearrangement keeps T-cel on T-cell pathway
Where does Maturation and Positive Selection occur? - Answer -Cortex of the thymus
Can negative selection also take place in the Cortex? - Answer -Yes, negative selection
can take place in the cortex at the same time as positive selection
Where does negative selection take place? - Answer -medulla of thymus
Where are mature thymocytes located? - Answer -Medulla
Where are immature thymocytes located? - Answer -Cortex
What special cells are in the Medulla - Answer -Dendritic cells, macrophages, and
medullary epithelial cells
, What special cells are in the cortex? - Answer -Cortical epithelial cells and
macrophages
Where can you find AIRE? - Answer -in the medullary epithelial cells
AIRE - Answer -Autoimmune regulator
made by medullary epithelial cells
Creates a couple hundred peripheral peptides that can be used to test T-cells for
negative selection
DiGeorge's syndrome - Answer -deletion in chromosome 22 in which thymus fails to
develop and T-cells are absent
Hassall's corpuscles - Answer -macrophages in both cortex and medulla remove the
many thymocytes that fail to mature properly
Involution of the Thymus - Answer -Progressively shrinks, fat gradually claiming areas
once packed with thymocytes
-reduces production of new T-cells
Double negative - Answer -No CD4 and CD8
Double Positive - Answer -CD4 and CD8 are present
Single Positive - Answer -has either CD4 or CD8
CD2 and CD5 - Answer -perform adhesion and signaling. They are present during
double negative stage
Thymocytes rearrange which 3 genes at the same time? - Answer -Beta, gamma, and
delta
pTalpha - Answer -surrogate alpha chain. signals cell to halt gamma, delta, Beta
chains, gene rearrangement and begin proliferation.
What do macrophages do in the thymus? - Answer -continually remove dead cells
How many rearrangements can successfully make a Beta chain? - Answer -up to 4
attempts
d:k light chain can have a minimum of how many rearrangements? - Answer -4
minimum attempts
