cell Development & Activation Questions and Answers
1. B cell development begins within
the and continues in
.: - Bone marrow (generation of BCRs and negative selection).
- Peripheral lymphoid organs (activation by Ag and Ab secretion).
2. Where does the B cell precursor rearrange its immunoglobulin genes in order to generate a B-cell
receptor?: Surface on bone marrow stromal cell.
3. What is negative selection of B cells?: Immature B cells that bind to self antigen removed from repertoire.
4. Activated B cells give rise to .: Plasma and memory cells.
5. Cognate interactions between are important for the pro- duction of
an immature B cell with IgM on its surface.: Pre-B cells (developing B cells) and bone marrow stromal cells.
6. What is happening in the early and late pro-B cell stages?: Heavy chain rearrangement (D-J in early, V-DJ
in late).
7. When is TdT active during B cell development? What is its function?: - During heavy chain
rearrangement (not light chain).
- Junctional diversity (adds N-nucleotides).
8. During the pro-B cell stages, there are chances for a produc- tive
heavy chain rearrangement.: 2 (V-DJ rearrangement on both chromosomes).
**Heavy chain rearranges first, then light chain.
9. What happens if no productive rearrangement occurs (heavy or light chain)?: Developing B cell
signaled to die by apoptosis (50% of cells).
10.Allelic exclusion gives BCRs with binding, while
no allelic exclusion gives BCRs with bind-
ing.: - Homogenous, high-avidity.
- Heterogenous, low-avidity.
**once one chain is productively rearranged, the other options are turned off.
11.What happens in the conversion from a pro-B cell to a large pre-B cell?: - Surrogate light chain exists and pre-
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, cell Development & Activation Questions and Answers
B cell receptor expressed on surface (of pre-B cell).
**It is called a large pre-B cell bc there is rapid expansion occurring.
12.What are the components of the surrogate light chain?: VpreB and gamma5.
13. Expression of
the surrogate light chain enables to
.: Rearranged heavy chain to access cell surface.
14.What happens if the pre-B cell receptor is never expressed on the surface of pre-B cells?: Clone dies.
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, cell Development & Activation Questions and Answers
15. Upon expression of the surrogate light chain and the pre-B cell receptor,
prior to light chain gene rearrangement provides another opportunity for diversity.:
Expansion of large (= proliferating) pre-B cells (all w/ same heavy chain with same variable regions but will soon have
different light chain so, recognized epitopes/Ag specificities will be unique).
16.Small pre-B cells have chances for successful light chain rearrangement.:
4 (kappa and lambda on each chromosome).
**No TdT during light chain rearrangement.
17.After a successful light chain rearrangement, the immature B cell now expresses on their surface.:
IgM ("real" BCR).
18.Once Surface IgM Appears the cells are referred to as immature B Cells and undergo .: Negative
selection.
**same as thymocyte negative selection, removal of high affinity self-reactive clones.
19.During negative selection, self Ag engaged immature B cells have a sec- ond opportunity to , this is
known as .: - Re- arrange light chains (if new receptor is still self-reactive, B
cell undergoes apoptosis after rearranging as many times as it can... if new receptor is no longer self-reactive, immature B
cell migrates to periphery and matures).
- Receptor editing (only on light chain).
20.How does receptor editing prevent immature B cells from engaging self Ags?: Immature B cell makes new
light chain and thus IgM with different specificity.
**If the newly rearranged receptor is self-reactive, light chain genes will contine rearranging. If not self-reactive,
B-cell leaves the bone marrow.
21.Receptor editing is a mechanism of establishing .: B cell
central tolerance.
22. After negative selection, the immature B cell expresses both
.: IgM (high affinity) and IgD (low affinity).
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1. B cell development begins within
the and continues in
.: - Bone marrow (generation of BCRs and negative selection).
- Peripheral lymphoid organs (activation by Ag and Ab secretion).
2. Where does the B cell precursor rearrange its immunoglobulin genes in order to generate a B-cell
receptor?: Surface on bone marrow stromal cell.
3. What is negative selection of B cells?: Immature B cells that bind to self antigen removed from repertoire.
4. Activated B cells give rise to .: Plasma and memory cells.
5. Cognate interactions between are important for the pro- duction of
an immature B cell with IgM on its surface.: Pre-B cells (developing B cells) and bone marrow stromal cells.
6. What is happening in the early and late pro-B cell stages?: Heavy chain rearrangement (D-J in early, V-DJ
in late).
7. When is TdT active during B cell development? What is its function?: - During heavy chain
rearrangement (not light chain).
- Junctional diversity (adds N-nucleotides).
8. During the pro-B cell stages, there are chances for a produc- tive
heavy chain rearrangement.: 2 (V-DJ rearrangement on both chromosomes).
**Heavy chain rearranges first, then light chain.
9. What happens if no productive rearrangement occurs (heavy or light chain)?: Developing B cell
signaled to die by apoptosis (50% of cells).
10.Allelic exclusion gives BCRs with binding, while
no allelic exclusion gives BCRs with bind-
ing.: - Homogenous, high-avidity.
- Heterogenous, low-avidity.
**once one chain is productively rearranged, the other options are turned off.
11.What happens in the conversion from a pro-B cell to a large pre-B cell?: - Surrogate light chain exists and pre-
1/8
, cell Development & Activation Questions and Answers
B cell receptor expressed on surface (of pre-B cell).
**It is called a large pre-B cell bc there is rapid expansion occurring.
12.What are the components of the surrogate light chain?: VpreB and gamma5.
13. Expression of
the surrogate light chain enables to
.: Rearranged heavy chain to access cell surface.
14.What happens if the pre-B cell receptor is never expressed on the surface of pre-B cells?: Clone dies.
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, cell Development & Activation Questions and Answers
15. Upon expression of the surrogate light chain and the pre-B cell receptor,
prior to light chain gene rearrangement provides another opportunity for diversity.:
Expansion of large (= proliferating) pre-B cells (all w/ same heavy chain with same variable regions but will soon have
different light chain so, recognized epitopes/Ag specificities will be unique).
16.Small pre-B cells have chances for successful light chain rearrangement.:
4 (kappa and lambda on each chromosome).
**No TdT during light chain rearrangement.
17.After a successful light chain rearrangement, the immature B cell now expresses on their surface.:
IgM ("real" BCR).
18.Once Surface IgM Appears the cells are referred to as immature B Cells and undergo .: Negative
selection.
**same as thymocyte negative selection, removal of high affinity self-reactive clones.
19.During negative selection, self Ag engaged immature B cells have a sec- ond opportunity to , this is
known as .: - Re- arrange light chains (if new receptor is still self-reactive, B
cell undergoes apoptosis after rearranging as many times as it can... if new receptor is no longer self-reactive, immature B
cell migrates to periphery and matures).
- Receptor editing (only on light chain).
20.How does receptor editing prevent immature B cells from engaging self Ags?: Immature B cell makes new
light chain and thus IgM with different specificity.
**If the newly rearranged receptor is self-reactive, light chain genes will contine rearranging. If not self-reactive,
B-cell leaves the bone marrow.
21.Receptor editing is a mechanism of establishing .: B cell
central tolerance.
22. After negative selection, the immature B cell expresses both
.: IgM (high affinity) and IgD (low affinity).
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