2.3.8 B-cell development Flashcards

1
Q

what is the major antibody secreting cell?

A

plasma cell

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2
Q

order of negative and positive selection in T cells and B cells

A

T-cells: Positive selection first, then negative
B-cell: Negative selection first, then positive

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3
Q

B cells develop in the ____ then go to the ______

A

BM, secondary lymphoid organs

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4
Q

T cells are derived from _____ in the ____, then go to the ______, then to the ______

A

stem cells
BM
thymus
secondary organs

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5
Q

both B and T cells are derived from the ______

A

hematopoeitc stem cell

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6
Q

what does a hematopoietic stem cell express that is a marker of immaturity?

A

CD34

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7
Q

what is a specific B cell marker that is only seen on B-cell precursors?

A

CD19

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8
Q

what is the specific marker for T cells?

A

CD3

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9
Q

what are the steps of b-cell maturation?

A
  1. heavy chain rearranged (u)
  2. light chain rearranged (kappa or lambda)
  3. wont see expression of IgMk or IgMl until immature B cell stage
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10
Q

_________ provides the IL7 signal

A

stromal cell

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11
Q

bone marrow stromal cells play an important role in what?

A

B-cell maturation

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12
Q

_____ is a critical cytokine in the development of B-cells

A

IL7

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13
Q

______ is critical for the development of T cells

A

Notch 1

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14
Q

Developing early B cells have a ______ receptor that allow it to bind IL7 cytokines and turn into an immature B cell

A

IL7 receptor

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15
Q

steps of rearrangement on B-cells

A
  1. heavy chains rearrange (if no rearrangement, go through apoptosis- 50% cells)
  2. light chains rearrange on first chromosome (if no rearrangement, move to second chromosome)
  3. light chains rearrange on second chromosome (if unsuccessful, apoptosis- 50%)
  4. productive light and heavy chain = pre-B cell
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16
Q

Pre-B receptors have a _____ light chain and when light chain rearrangement takes place a functional B-cell receptor is expressed.
What are also parts of the B cell receptor that sends signals to the cell interior?

A

Surrogate
IgB and IgA

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17
Q

can successful rearrangement happen on both the maternal and paternal chromosome heavy chains?

A

no! can only be on one, when a successful rearrangement happens, the other chromosome is shut down

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18
Q

During light chain rearrangement, _____ is first, and if that is unsuccessful then _____ is rearranged. if both are unsuccessful, apoptosis happens

A

Kappa (on first then second chromosome)
Lambda (on first then second chromosome)

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19
Q

what is the ratio of kappa: lambda light chains?

A

2:1

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20
Q

how many checkpoints are there in B-cell development?

A

2: heavy chain and light chain checkpoints

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21
Q

what are the functions of the following proteins?
1. IL-7 receptor
2. Ig-alpha, Ig-Beta
3. CD-19

A
  1. growth factor receptor
  2. signaling protein
  3. signal transduction, specific marker for B-cells too
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22
Q

what are the differences between the B1 and B2 lineages?

A

B1:
- first B-cells produced in bone marrow before birth
-can self replicate
-result in: short lived plasma cell

B2:
- start production after birth
- result in: short AND long lived plasma cells

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23
Q

do B1 cells disapear after birth?

A

no

24
Q

where can you find short-lived plasma cells?

A

medullary cords or red pulp of spleen

25
Q

the isotypes secreted from B1 cells are ______ and for B2 cells the isotypes are ______

A

B1: IgM
B2: IgG > IgM

26
Q

do B1 cells require T cell help? what about B2?

A

B1 cells do not require T cell help, but B2 cells do

27
Q

if an immature B cell does not recognize self, what happens?

A

goes out in blood and acquires IgD

28
Q

if an immature B cell does recognize self, what happens?

A

it is retained in BM, goes through self-editing in light chain to try to become non-self reactive.
-if it does produce a non-self reactive B cell it can leave BM
-if it does NOT produce a non-self reactive B cell, it goes through apoptosis

29
Q

what happens if IgM on surface of self-reacting B-cells reacts with a soluble univalent self antigen?

A

it becomes anergic

30
Q

what is peripheral tolerance? what happens?

A

when self antigen develops outside of BM, B-cells either die or become anergic

31
Q

how does a B-cell move through a lymph node?

A

enters HEV –> primary lymph node follicle –> become mature naive B cell –> leave by efferent

32
Q

explain the interaction of B-cells with FDCs and chemokines!
What kind of selection is this?

A

B-cells come into HEV –> chemokines attract B-cells to primary follicle –> interact with FDC –> drives maturation of immature B-cells –> mature B-cells leave lypmh node

  • positive selection
33
Q

Is the FDC derived from the hematopoietic stem cell? Does it belong to the dendritic family?

A

no and NO!

34
Q

why is FDC called a dendritic cell?

A

it displays dendritic extensions where b-cells can interact for signals of maturation

(if B-cells dont interact with FDC, they become apoptotic)

35
Q

B-cell leaves the bone marrow as a ______ with which chains rearranged?

A

immature B-cell

Both light and heavy

36
Q

where are plasma cells found in the lymph node?

A

medullary cords

37
Q

are plasma cells usually found in the blood circulation?

A

NO this means something is wrong!

38
Q

________ make antibodies for micro-organisms outside cells, and _____ deal with micro-organisms inside the cells

A

B-cells
T-cells

39
Q

what are 3 things antibodies can do?

A

1.neutralization
2. opsonization
3. complement activation

40
Q

when do B cells become activated?

A

when their receptors are cross-linked by antigens

41
Q

Activation signal is transmitted to cytoplasm by ______

A

Ig-alpha and Ig-Beta

42
Q

______ is part of the co-receptor and is a specific marker for B cells. what are the other parts of the co-receptor?

A

CD19
-CD21 (CR2), CD81

43
Q

what are the T-cell co-receptors?

A

CD28, B7

44
Q

T cells express ______ and dendritic cells express ____

A

Cd28
B7

45
Q

what are the 2 responses B cells can have to antigens?

A

T-dependent and T-independent

46
Q

T-dependent responses all involve the _____ lineage and T-independent responses all involve the ____ lineage

A

B2
B1

47
Q

The T-cell subset involved in T-dependent antibody responses are called the ____ subset. This has recently been split up into what?

A

TH2
TH2/TfH

48
Q

what is the difference between TH2 and TfH subsets?

A

TH2 leaves lymph node as an effector cell
TfH cell goes to B-cells region of lymph node

49
Q

TH2-TfH responses are associated with _______ (4) and inhibited by _______(2)

A
  • IL4, IL6, IL10, IL13
  • IL12, Gamma-IF
50
Q

IL12 is made by ________

A

macrophages or dendritic cells

51
Q

T-dependent responses by B-cells involve _______ T-cells of the TfH subset

A

CD4+

52
Q

are T-dependent or T-independent used for the majority of responses?

A

T-dependent

53
Q

basic steps of T-dependent activation

A
  1. B cell associates with antigen
  2. MHCII recognized by Helper T
  3. T-cell releases cytokines and drives B cell to differentiate into plasma cell
54
Q

what are the 2 different signals involved in activation process?

A
  1. First signal: B-cell interacting with its specific antigen through B-cell receptor
  2. Second signal: interactions of TCR with MHCII on surface of B cell that has the processed antigen
    CD40 on B cell must interact with ligand CD40-L on T-cell
55
Q

when is antibody produced?

A

after B-cell differentiates into plasma cell