PCB 3233 - Immunology Exam 4
Questions and Answers Latest
Version 2025 Graded A+
Positive Selection
makes sure that your T-Cell recognizes one of your
MHC.
If it does not, then apoptosis
Negative Selection
Makes sure it does not recognize your peptide:MHC
too strongly
Does gamma: delta T-cells have to go through
positive selection?
No
What does turning off RAG 1&2 do to your gene
rearrangement?
Preserve the current rearrangement
Primary Lymphoid Tissue
bone marrow and thymus
What does TH1 cells do?
Activate macrophages
Thymal Stromal Cells
Keeps BCR genes closed and opens TCR genes
,IgM activates?
complement
Notch-1
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?
Cortex of the thymus
Can negative selection also take place in the
Cortex?
Yes, negative selection can take place in the cortex
at the same time as positive selection
Where does negative selection take place?
medulla of thymus
Where are mature thymocytes located?
Medulla
Where are immature thymocytes located?
Cortex
What special cells are in the Medulla
Dendritic cells, macrophages, and medullary
epithelial cells
What special cells are in the cortex?
, Cortical epithelial cells and macrophages
Where can you find AIRE?
in the medullary epithelial cells
AIRE
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
deletion in chromosome 22 in which thymus fails to
develop and T-cells are absent
Hassall's corpuscles
macrophages in both cortex and medulla remove the
many thymocytes that fail to mature properly
Involution of the Thymus
Progressively shrinks, fat gradually claiming areas
once packed with thymocytes
-reduces production of new T-cells
Double negative
No CD4 and CD8
Double Positive
CD4 and CD8 are present
Questions and Answers Latest
Version 2025 Graded A+
Positive Selection
makes sure that your T-Cell recognizes one of your
MHC.
If it does not, then apoptosis
Negative Selection
Makes sure it does not recognize your peptide:MHC
too strongly
Does gamma: delta T-cells have to go through
positive selection?
No
What does turning off RAG 1&2 do to your gene
rearrangement?
Preserve the current rearrangement
Primary Lymphoid Tissue
bone marrow and thymus
What does TH1 cells do?
Activate macrophages
Thymal Stromal Cells
Keeps BCR genes closed and opens TCR genes
,IgM activates?
complement
Notch-1
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?
Cortex of the thymus
Can negative selection also take place in the
Cortex?
Yes, negative selection can take place in the cortex
at the same time as positive selection
Where does negative selection take place?
medulla of thymus
Where are mature thymocytes located?
Medulla
Where are immature thymocytes located?
Cortex
What special cells are in the Medulla
Dendritic cells, macrophages, and medullary
epithelial cells
What special cells are in the cortex?
, Cortical epithelial cells and macrophages
Where can you find AIRE?
in the medullary epithelial cells
AIRE
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
deletion in chromosome 22 in which thymus fails to
develop and T-cells are absent
Hassall's corpuscles
macrophages in both cortex and medulla remove the
many thymocytes that fail to mature properly
Involution of the Thymus
Progressively shrinks, fat gradually claiming areas
once packed with thymocytes
-reduces production of new T-cells
Double negative
No CD4 and CD8
Double Positive
CD4 and CD8 are present
