14: B cell activation and Ab production I Flashcards

1
Q

how do B cells develop

A

from bone marrow precursors in the absence of ag

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

how are humoral immune responses activated

A

recognition of Ags by BCR

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

what do Ag do to B cells

A

activate naive by binding membrane IgM and IgD

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

structure of IgM

A

pentamere w/ 5 subunits

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

how many Abs can be produced from a single B cell

A

5000 Abs cells per week

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

what is the peak humoral immune response per day

A

10^12 Abs

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

what causes the proliferation of activated B cells

A

Ags, T helper cells and other stimuli

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

what can a clonal B cell become

A

plasma cell, or other IG isotype or may undergo affinity maturation or memory cells

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

what is also activated with B cells by Ag binding

A

more costimulatory molecules produced

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

how does B cell proliferation happen in relation to T cell

A

downstream of it by CD 40L

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

what causes isotype switching

A

intracellular pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what do plasma cells do

A

secrete antibodies

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

what B cells become memory or have affinity maturation

A

High affinity Ig expressing B cells

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

primary antibody infection starts with

A

short lived plasma B in LO, more IgM than Ig G then low level Ab production and long lived plasma cells in bone marrow f

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

secondary antibody respones

A

Memory B then Plasma for more IgG and long lived plasma cells in bone marrow and Memory B cell levels increase

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

what happens to naive B cells in primary immune response

A

stimulated by Ag to activate and be Ab secreting for more IgM than IgG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

secondary immune response on B cells

A

same Ag stimulates memory B cells for more IgG than IgM

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

which is difference btwn secondary and primary immune response

A

secondary produces more Abs faster

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what part changes for isotype switching

A

heavy chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is induced by Ag Ab binding

A

affinity maturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what immune response has affinity maturation

A

secondary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

primary is induced by what Ags

A

any type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what Ags produce secondary immune response

A

mainly proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

follicular B cells respond to and initiate what

A

protein Ags for T dependent Ab resonse for helper T cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is another name for follicular B cells

A

B 2 cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

which B cell produces long-lived plasma cells

A

B2 or F B cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

waht do Marginal B cells respond to and initiate

A

multivalent Ags for T independent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what do B1 cells respond to and induce

A

multivalent Ags at mucosal sites and are T independent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what is another name for MZ B cells

A

B2 cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what Ig is produced by MZ and B1 cells

A

IgM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

usual target of B1 cells

A

carbohydrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

memory B cells usually come from

A

B2 cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

where are B2 cells usually

A

throughout body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

how are B2 cells replaced

A

continually by bone marrow in adult life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

where do B1 cells come from

A

fetal liver during the 8th week of gestation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what do B1 cells represent

A

transitional type of lymphocyte to bridge innate and adaptive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

problem with B1 cells

A

not very diverse and limited compared to B2 cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what are B1 Abs directed against

A

conserved microbial Ags

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

transport of Ags to B cells

A

have to be captured and taken to B cells in lymphoid organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

where are B cells located at in Lymphoid organs

A

follicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

other names for follicular B cells

A

recirculating or B2 Cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

how do F B cells recirculate

A

from one to another secondary lymphoid organ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

secondary lymphoid organs

A

spleen, lymph nodes and mucosal lymphoid tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

follicles are in what

A

secondary lymphoid organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

what guides the movement of B cells

A

CXCL13 chemokine

46
Q

where does CXCL13 come from

A

Follicular DCs

47
Q

what is not expressed by FDCS

A

MHC Class II

48
Q

what can an FDC not do

A

phagocytose and process Ags for Class I MHC

49
Q

what immune response to FDCs help in

A

adaptive immunity

50
Q

what else is guided by CXCL13 besides B cells

A

TFH cells

51
Q

how long can an FDC have an immune complex on its surface

A

weeks to months

52
Q

what mediates Ag retention by FDCs

A

FcyRIIb Fc receptor as well as CR1, CR2 (CD 21) complement receptors

53
Q

what do the immune complexes of FDCs drive

A

antibody affinity maturation

54
Q

what plays a role in germinal center reactions

A

FDC receptors

55
Q

how are Ags presented to B cells

A

in intact native conformation and not processed by APCS

56
Q

how are small B cells delivered to follicles

A

afferent lymphatics and conduits

57
Q

how are large Ags delivered to B cells

A

subcapsular sinus macrophages or DCs in medulla

58
Q

how do afferent lymphatics drain in LN

A

into the subcapsular sinus of the LNs

59
Q

soluble Ags properties and how they reach B cells in LN

A

smaller than 70 kD and get to follicles for direct interaction

60
Q

transport of large Ags in LN

A

captured by resident FDCs and transported to activated B cells in follicles

61
Q

how are microbes and Ag-Ab complexes taken to B cells in LN

A

captured by subcapsular sinus macrophages and deliver Ags to follicles

62
Q

where are T cells located in marginal zones

A

periarteriolar lymphoid sheaths (PALS)

63
Q

distinctive cell types in marginal zones

A

MZ macrophages and marginal B cells

64
Q

what is the marginal zone

A

barrier between red pulp and white pulp of spleen

65
Q

which part of the spleen houses lymphocytes

A

white pulp

66
Q

how do lymphocytes and DC enter the white pulp

A

marginal sinus between marginal zone and white pulp

67
Q

how do Ag in immune complexes bind B cells

A

CR2 complement receptors on MZ B cells

68
Q

what is the role of MZ B cells with immune complex Ags

A

transfer to follicular DCs

69
Q

how are blood borne pathogens handled

A

captured by pDCs and transported to spleen for MZ B cells

70
Q

what in spleen captures polysaccharide Ag

A

MZ macrophages to give to MZ B cells

71
Q

how are MZ B cells independent of BCRs

A

bind complexes with AG and coat in CR complement fragments to shuffle them to follicular region

72
Q

where do FDCs express high levels of CR

A

follicles to compete for binding to Ags presented by MZ B cells

73
Q

what happens after CR on FDC binds Ag

A

MZ B cells go back to MZ

74
Q

what are MZ B cells to B2 follicular cells

A

shuttle for Ags

75
Q

when is a T dependent response required

A

protein Ags for help of CD4+ T helper cells

76
Q

which T cells help B cells and how

A

TFH leads to the formation of germinal centers to activate B cell proliferation

77
Q

which Ags use T indepentent

A

multivalent Ags such as polysaccharides, lipids, and nucleic acids

78
Q

how do TI responses work

A

BCR binding and potentiated signals from other receptors on B cells

79
Q

what potentiates B cell activation

A

CR2 and TLRs

80
Q

role of CR 2(CD21) on BCR

A

binds C3d on microbe while Ag bind BCR as a co-receptor

81
Q

microbe bound by CR2 is coated in

A

complement

82
Q

how is complement activated in B cell response

A

non-microbial polysaccharides or microbe itself.

83
Q

2nd form to cause B cell activation

A

PAMP recognition by TLRs at same time as Ag binding to BCR

84
Q

what does F B cell survival depend on

A

signals from BCR and inputs from BAFF

85
Q

how does BAFF work

A

provides maturation and survival signals through its receptor

86
Q

what produced BAFF

A

myeloid cells in lymphoid follicles and bone marrow

87
Q

parts of BCR signaling for activation

A

BCR binding initiates then internalizes bound Ag into endosomal vesicles

88
Q

how is protein Ag presented to

A

processed and presented as MHC II on B cell surface for TH cell to recognize

89
Q

what happens after TH cells recognize MHC II peptide complexes

A

stimulate B cell response

90
Q

what response is B cell presenting to T cell

A

hapten carrier conjugates

91
Q

what on BC helps TH recognize Ag and activate it

A

CD40 that binds CD40L on THC

92
Q

what does activate THC in TCD response cause

A

activated B cells for proliferation

93
Q

what does BT interaction lead to

A

isotype switching and shortlived plasma cells

94
Q

what are germinal centers for

A

B cells mutate, affinity maturation, ISOT switch, memory cells and long lived plasma cells

95
Q

extrafollicular B cell response goes where

A

medullary cords of LN and junction between TC zone and red pulp of spleen

96
Q

what are the two B cell T dependent responses

A

Extrafollicular and Follicular/Germinal centers

97
Q

which B cell T dependnent response has more everything

A

Follicular

98
Q

what must happen for TfH cells to activate B cells

A

activation of T cells by DCs then by activated B cells to go to Germinal centers to activate more B cells

99
Q

which cytokine helps develop GC B cells and plasma cells

A

IL 21

100
Q

what controls isotype switcing from TFH cells

A

IFNy and IL4

101
Q

when are TFH cells made from activated T cells

A

4-7 days after Ag exposure

102
Q

what to TFH cells express

A

inducible costimulators, PD1, IL 21, Bcl-6

103
Q

what do Dark zones in follicles mean

A

center of GC where B cells are proliferating

104
Q

what happens to B cells in germinal centers dark zone

A

extensive isotype switching and somatic hypermutation of IgV gene

105
Q

what happens in light zones of GC

A

encounter FDCs with Ags and TFH cells

106
Q

which B cells survive and what do they become

A

highest affinity Ig receptors and become Ab secreting and memory B cells

107
Q

where to Ab secreting B cells go

A

bone marrow as long lived plasma cells

108
Q

where do memory B cells go

A

recirculating lymphocyte pools

109
Q

stains dark zones of GCs

A

antiKi67 Ab

110
Q

stains light zones of GCs

A

anti CD 23 on FDCs

111
Q

what causes activated B cells to go to T cell zones

A

CCR7