IMMUNOLOGY CHAPTER 8 KUBY
EXAM QUESTIONS WITH CORRECT
ANSWERS
Where does T cell development occur? - Correct Answers -T-cell development occurs in
the thymus
Thymus - Correct Answers -· the thymus is the primary lymphoid organ in our chest
cavity.
· Thymocytes are produced throughout our lifetime, after puberty the thymus shrinks
and produces fewer and fewer T cells
T cell development stage 1 - Correct Answers -1. begins with the arrival of immature
lymphocyte precursors migrating from the bone marrow via chemokine receptors, they
travel through the blood, and into the thymus
T cell development stage 4 - Correct Answers -4. T-cell precursors then travel to the
outer thymic cortex, where they proliferate and begin to express their T-cell receptors.
T cell development stage 5 - Correct Answers -5. T cells that survive the stringent
selection processes mature and migrate into the thymic medulla before exiting where
they arrived, at the corticomedullary junction
Positive/negative selection stages for T cells - Correct Answers -• Double negative (DN)
cell
has no CD4 or CD8 (CD4-
CD8-)
• Double positive cell (DP)
is both CD4+CD8+
T cell development stage 2 - Correct Answers -2. Once in the thymus, they proliferate,
differentiate, and undergo selection processes that reduce their numbers by 95%, yet
generate a diverse population of naïve CD4+ and CD8+ T cells.
T cell development stage 3 - Correct Answers -3. After arriving in the thymus, T-cell
precursors encounter Notch ligands, which are abundantly expressed by the thymic
epithelium.
, a. The commitment of stem cells to the T-cell lineage is dependent on Notch, a
receptor.
Double negative (DN) T cell - Correct Answers -a. The earliest T cells lack detectable
CD4 and CD8 and are therefore referred to as double negative (DN) cells.
How are DN T cell stages categorized? - Correct Answers -DN T cells can be divided
into four subsets based on the presence or absence of other cell surface molecules (c-
kit CD117, the receptor for stem cell growth factor, CD44, an adhesion molecule, and
CD25, the a chain of the interleukin (IL)-2 receptor):
DN1 stage - Correct Answers -· DN1 includes c-Kit (CD117)++, CD44++, and CD25-
a. still multipotent, they receive Notch signals immediately on entering the thymic
environment and begin to restrict themselves to the T-cell lineage.
They travel to the cortex, where they proliferate and gain expression of CD25
DN2 stage - Correct Answers -DN2 includes c-Kit (CD117)++, CD44+, and CD25+
a. the genes for the TCR γ, δ, and β chains rearrange (Takes place in the subcapsular
cortex)
b. The TCR α-chain locus does not yet rearrange.
c. At the late DN2 stage, T-cell precursors fully commit to the T-cell lineage and reduce
expression of both c-Kit and CD44.
DN3 stage - Correct Answers -a. continue to rearrange their TCR γ, TCR δ, and TCR β
chains and make the first major decision in T-cell development: whether to join the
TCR-γδ or TCR-αβ T-cell lineage.
Those DN3 T cells that successfully rearrange their β chain typically commit to the
TCR-αβ T-cell lineage.
b. They lose expression of CD25, halt proliferation
DN4 stage - Correct Answers -a. matures directly into CD4 CD8 DP thymocytes.
b. a-chain rearrangement begins at the DN4 stage
c. Allelic exclusion of beta chain locus+
What commits stem cells to the T cell lineage? - Correct Answers -a. The commitment
of stem cells to the T-cell lineage is dependent on Notch, a receptor.
EXAM QUESTIONS WITH CORRECT
ANSWERS
Where does T cell development occur? - Correct Answers -T-cell development occurs in
the thymus
Thymus - Correct Answers -· the thymus is the primary lymphoid organ in our chest
cavity.
· Thymocytes are produced throughout our lifetime, after puberty the thymus shrinks
and produces fewer and fewer T cells
T cell development stage 1 - Correct Answers -1. begins with the arrival of immature
lymphocyte precursors migrating from the bone marrow via chemokine receptors, they
travel through the blood, and into the thymus
T cell development stage 4 - Correct Answers -4. T-cell precursors then travel to the
outer thymic cortex, where they proliferate and begin to express their T-cell receptors.
T cell development stage 5 - Correct Answers -5. T cells that survive the stringent
selection processes mature and migrate into the thymic medulla before exiting where
they arrived, at the corticomedullary junction
Positive/negative selection stages for T cells - Correct Answers -• Double negative (DN)
cell
has no CD4 or CD8 (CD4-
CD8-)
• Double positive cell (DP)
is both CD4+CD8+
T cell development stage 2 - Correct Answers -2. Once in the thymus, they proliferate,
differentiate, and undergo selection processes that reduce their numbers by 95%, yet
generate a diverse population of naïve CD4+ and CD8+ T cells.
T cell development stage 3 - Correct Answers -3. After arriving in the thymus, T-cell
precursors encounter Notch ligands, which are abundantly expressed by the thymic
epithelium.
, a. The commitment of stem cells to the T-cell lineage is dependent on Notch, a
receptor.
Double negative (DN) T cell - Correct Answers -a. The earliest T cells lack detectable
CD4 and CD8 and are therefore referred to as double negative (DN) cells.
How are DN T cell stages categorized? - Correct Answers -DN T cells can be divided
into four subsets based on the presence or absence of other cell surface molecules (c-
kit CD117, the receptor for stem cell growth factor, CD44, an adhesion molecule, and
CD25, the a chain of the interleukin (IL)-2 receptor):
DN1 stage - Correct Answers -· DN1 includes c-Kit (CD117)++, CD44++, and CD25-
a. still multipotent, they receive Notch signals immediately on entering the thymic
environment and begin to restrict themselves to the T-cell lineage.
They travel to the cortex, where they proliferate and gain expression of CD25
DN2 stage - Correct Answers -DN2 includes c-Kit (CD117)++, CD44+, and CD25+
a. the genes for the TCR γ, δ, and β chains rearrange (Takes place in the subcapsular
cortex)
b. The TCR α-chain locus does not yet rearrange.
c. At the late DN2 stage, T-cell precursors fully commit to the T-cell lineage and reduce
expression of both c-Kit and CD44.
DN3 stage - Correct Answers -a. continue to rearrange their TCR γ, TCR δ, and TCR β
chains and make the first major decision in T-cell development: whether to join the
TCR-γδ or TCR-αβ T-cell lineage.
Those DN3 T cells that successfully rearrange their β chain typically commit to the
TCR-αβ T-cell lineage.
b. They lose expression of CD25, halt proliferation
DN4 stage - Correct Answers -a. matures directly into CD4 CD8 DP thymocytes.
b. a-chain rearrangement begins at the DN4 stage
c. Allelic exclusion of beta chain locus+
What commits stem cells to the T cell lineage? - Correct Answers -a. The commitment
of stem cells to the T-cell lineage is dependent on Notch, a receptor.
