Development of B-cells Flashcards

1
Q

What are the six phases of B-cell development?

A
  1. Repertoire assembly
  2. Negative selection
  3. Positive selection
  4. Searching for infection
  5. Finding infection
  6. Attacking infection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The first 3 phases of B-cell development occur in ______, while the last 3 phases occur in ______.

A
  1. Bone marrow
  2. Blood vessels & lymphatics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which hematopoietic cell can differentiate into a B-cell or T-cell?

A

Common lymphoid progenitor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which of the following transmembrane proteins is the only one present on pluripotent hematopoietic stem cells?

  • CD10
  • CD34
  • CD127
  • CD19
A

CD34

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

True or false. When a B-cell precursor differentiates into a pro-B cell, it is no longer capable of self-renewal.

A

False. Pro-B cells are able to self-renew

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Dh and Jh joining occurs in _____ cells

A

Early pro-B cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Vh segment joins DJh segment in _____ cells

A

Late pro-B cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Expression of functional μ chains occurs in _____ cells

A

Large pre-B cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Light chain rearrangement and assembly with μ-chain occurs in ______ cells

A

Small pre-B cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Membrane-bound IgM associates with Igα and Igβ in ______ cells

A

Immature B cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Is the light chain or heavy chain more specific?

A
  • Light chain is more specific
  • If the body makes a good heavy chain, it will amplify the population of cells that can express that heavy chain so light chains can be processed from there
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

A ______ of growth factors and transcription factors drive immune cell differentiation

A

Gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

___% of pre-B cells go on to become immature B-cells

A

50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the function of stromal cells in bone marrow?

A

Make contact with maturing B cells and secrete growth factors for maturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

True or false. The default pathway for B-cell development is to die by apoptosis unless a survival signal is received.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the difference between productive and nonproductive rearrangement?

A
  • Productive - complete and functional Ig produced from rearranged genes
  • Nonproductive - rearrangement does not translate into a functional Ig
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the consequence of not having a functional Rag gene on either chromosome?

A

No rearragement can occur to create antibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the two criteria requirements for a pro-B cell to survive?

A
  1. Make a μ chain
  2. μ chain must be able to bind to a light chain (surrogate chain)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the two components of the surrogate light chain and function to mediate binding to receptors on stromal cells?

20
Q

How does a pro-B-cell initiate pre-B-cell receptor assembly?

A
  1. Igβ shuts down RAG gene transcription
  2. RAG proteins are degraded
  3. Chromatin Structural changes prevent gene rearrangement
21
Q

What is allelic exclusion?

A

When a cell only expression one of its two copies of a gene

22
Q

What is allelic exclusion?

A

Cell only expresses one copy of its two genes

23
Q

What is the consequence of not having allelic exclusion in B-cell receptor formation?

A

Low avidity binding

24
Q

___% of pre-B-cells have productive rearrangement

25
RAG is expressed in what stages of B cell development?
* Early pro-B * Late pro-B * Large pre-B * Immature B
26
Kit (growth factor receptor) is expressed in what stages of B-cell development?
* Stem cell * Early pro-B
27
IL-7 (growth factor receptor) is expressed in what stages of B-cell development?
* Stem cell * Early pro-B * Late pro-B * Large pre-B
28
CD25 (growth factor receptor) is expressed at what stages of B-cell development?
* Late pro-B * Large pre-B
29
RAG1 and RAG2 are expressed in what stages of B-cell development?
* Early pro-B * Late pro-B * Immature B
30
λ5 and VpreB are expressed in what stages of B-cell development?
* Early pro-B * Late pro-B * Large pre-B * Small pre-B
31
Of the two B-cell populations (B1 and B2), what is the difference between their modes of renewal?
* B1: self-renewing * B2: replaced from bone marrow
32
B1 cells make up approximately \_\_\_% of B-cells
* ~5% * Less diverse than B2
33
Why do B1 cells have a lower affinity for their antigens than B2 cells?
* Polyspecific * Recognize bacterial polysaccharides, not proteins
34
Where are B-cells typically found?
* Blood * Lymph * Secondary lymphoid organs * Bone marrow
35
\_\_\_\_% of immature B-cells bind self-antigen
75%
36
In what stage of B cell development does negative selection occur?
Immature B-cells
37
What are the two potential fates of an immature B cell during negative selection?
* If it doesn't recognize self-antigen, it ends the blood and expresses IgD and IgM * If it does recognize self-antigen, it is retained in the bone marrow and given a second chance to rearrange light chain
38
\_\_\_\_\_ is a state of nonresponsiveness to an antigen
Anergy
39
What is the life span of an anergic B-cell vs. a normal B-cell?
* Anergic: ~1-5 days * Normal: ~40 days
40
What are the possible fates for self-reactive B-cells in the **bone marrow** (central tolerance)?
* Receptor editing * Apoptosis * Anergy
41
What are the possible fates for self-reactive B-cells in the periphery? (Peripheral tolerance).
* Apoptosis * Anergy
42
What is the function of high endothelial venules (HEV) in secondary lymph organs?
Delivery of B-cells (mature and immature) to lymph nodes in search of their corresponding antigens.
43
What is the function of chemokines?
Attracts B-cells
44
What chemokine is expressed in lymph node cortices and dendritic cells in lymph nodes?
CCL21
45
What chemokine is expressed solely on B-cells?
CCR7
46
What chemokine is expressed by dendritic cells in lymph nodes to attract B cells?
CCL19
47
\_\_\_\_\_\_ are specialized stromal cells not of hematopoietic origin that secrete CXCL13 to attract B-cells to the primary follicle for maturation.
Follicular dendritic cells (FDCs)