Humoral Responses Flashcards
1
Q
secreted antibodies bind to
A
- extracellular microbes
2
Q
following binding of antibodies to extracellular microbes
A
- microbes are ingested by phagocytic cells
3
Q
what enhanced the microbe-killing abilities of phagocytic cells
A
- helper T cells
4
Q
function of helper T cells
A
- recruit leukocytes to destroy microbes
- strengthen epithelial barrier to expel microbes
5
Q
when B cells engage polysaccharide or lipid antigen
A
- plasma cells secrete IgM only
6
Q
when B cells engage protein antigen only
A
- requires assistance from CD4+ helper T cells for full response
7
Q
B cells acting as antigen presenter cells for protein antigen
A
- ingest protein antigen
- degrade them
- display peptides bound to MHC II for recognition by helper T cells
8
Q
how helper T cells activate B cells
A
- express cytokine and cell surface proteins
- work together to activate B cells
9
Q
specificity of the antibodies secreted by B cells
A
- exactly like the antigen-binding specificity as the starting B cell receptor
- one B cell makes one antibody of one specificity to one epitope
10
Q
using polysaccharides and lipids as antigen only
A
- stimulates synthesis of IgM
11
Q
using protein antigens with help from helper T cells
A
- production of IgG, IgA, and IgE antibodies
12
Q
isotype switching
A
- making different antibodies
- same specificity
13
Q
affinity maturation
A
- helper T cells stimulate production of antibodies with higher affinity for the antigen
14
Q
naive B cell has which antibodies on it surface
A
- IgM
- IgD
15
Q
Do B cells need fragments or whole molecules for recognition?
A
- whole molecules
16
Q
antibody molecules composed of
A
- two identical light chains
- two identical heavy chains
17
Q
antigen binding fragment
A
- Fab region
18
Q
what recognizes the Fc region
A
- macrophages
- neutrophils
- mast cells
- basophils
- eosinophils
- have Fc receptors
19
Q
IgA found
A
- mucosal areas
- nose
- breathing passages
- digestive tract
- ears
- eyes
- vagina
20
Q
IgA antibodies protect
A
- body surfaces exposed to outside foreign antigen
- mucosal immunity
21
Q
IgG antibodies found
A
- in all body fluids
22
Q
IgG antibodies compared to other antibodies
A
- most common antibody of all the antibodies in the body
- only antibody that can cross the placenta
23
Q
IgG antibodies important in
A
- fighting bacterial and viral infections
- opsonization
- complement activation
- antibody-dependent cell mediated cytotoxicity
- neonatal immunity
- feedback inhibition of B cells
24
Q
IgM antibodies compared to other antibodies
A
- they are the largest antibody
- pentamer
25
IgM antibodies found
- in blood and lymph
26
IgM antibodies importance
- first type of antibody made in response to an infection
- naive B cells antigen receptor
- complement activation
27
IgE antibodies found
- lungs
- skin
- mucous membranes
28
IgE antibody importance
- involved in allergic reactions (mast cell hypersensitivity)
- cause the body to react against foreign substances like pollen, fungus spores, and animal dander
- high in people with allergies
- defense against helminthic parasites
29
IgD antibodies found
- surface of newly matured B cells
30
which antibody is best with neutralization
- IgG
| - IgA
31
which antibody is best for opsonization
- IgG1
32
which antibody is best for sensitization of mast cells
IgE
33
which antibody is best for complement activation
- IgM
| - IgG3
34
which antibody can transport across epithelium
- IgA
35
which antibody can transport across the placenta
- IgG1
36
which antibody can diffuse into extravascular sites
- IgG
37
B cell maturation process
- stem cell
- Pro-B
- Pre-B
- immature B
- mature B
38
Ig expression of mature B
- membrane IgM and IgD
39
mature B cells are called
- follicular B cells
| - found in lymph node and spleen follicles
40
marginal zone B cells found
- margins of the splenic follicles
41
marginal zone B cells develop
- from the same progenitors as do follicular B cells
42
B-1 lymphocytes found
- in lymphoid organs
| - peritoneal cavity
43
B-1 lymphocyte development
- may develop early
| - may develop from different precursors
44
follicular B cells with protein antigen + helper T cells
- isotope switched
- high affinity antibodies
- long lived plasma cells
45
marginal zone B cells with lipid, polysaccharides
- mainly IgM
| - short lived plasma cells
46
B-1 cells with lipid, polysaccharides
- mainly IgM
| - short lived plasma cells
47
primary response lag after immunization
- 5-10 days
48
secondary response lag after immunization
- 1-3 days
49
primary response peak response
- smaller
50
secondary response peak response
- larger
51
primary response antibody isotype
- IgM>IgG
52
secondary response antibody isotype
- increase in IgG
| - sometimes IgA or IgE
53
primary response antibody affinity
- lower average affinity
| - more variable
54
secondary response antibody affinity
- higher average affinity
| - affinity maturation
55
C3d
- breakdown product of C3b
- binds B cells through complement receptor type 2
- CR2 or CD21
56
engagement of CR2 by C3d
- enhances antigen-dependent activation responses of B cells
57
B cells and toll-like receptors
- B cells express numerous toll-like receptors
58
TLR engagement on B cell by microbial products
- triggers activating signals that work in concert with signals from B cell receptor
59
Expression of TLRs in B cells
- provides a cell-intrinsic mechanism for innate signals regulating adaptive immune responses
60
functional consequences of B cell activation by antigen
- entry into cell cycle: mitosis
- increased expression of cytokine receptors
- low-level IgM secretion
61
significance of entry into cell cycle, mitosis
- clonal expansion
62
significance of increased expression of cytokine receptors
- ability to respond to cytokines produced by helper T cells
63
significance of migration out of lymphoid follicles
- interaction with helper T cells
64
significance of secretion of low levels of IgM
- early phase of humoral immune response
65
activation of CD4 helper T cells and B cells
- independently activated by a protein antigen
| - in different regions of a lymph node
66
CD4s activated where in lymph node
- extra follicular
67
B cells activated where in lymph node
- follicle
68
B cells present antigen on
- MHC II
69
activated helper cells express
- CD40 ligand
| - SUPER IMPORTANT FOR ACTIVATING B cells
70
activated helper cells secrete
- cytokines
| - act on B cells to initiate proliferation and differentiation to plasma cells
71
After B and helper T cells are activated, where do they go
- migrate back to follicle
| - B cells proliferate
72
what forms while B cells proliferate
- a germinal center
73
proliferating germinal center B cells undergo
- somatic mutation of antibody gene variable regions
| - Ig heavy-chain isotype switching
74
what is selected in the germinal center
- high affinity B cells
| - results in production of high affinity antibodies
75
high affinity antibodies leads to generation of
- long-lived plasma cells
| - memory B cells
76
where do long-lived plasma cells migrate to
- bone marrow
| - where they secrete IgG
77
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what cytokine helps with class switching to IgG
- secreted by
```
- interferon gamma
| - Th1
78
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what cytokine helps with class switching to IgE
- secreted by
```
- IL-4
| - Th2
79
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what cytokine helps with class switching to IgA
- secreted by
```
- TGF-B
| - BAFF
80
how to get affinity maturation
- have already undergone somatic mutation and have different affinities for antigen
- B cells with high affinity membrane Ig bind antigen on follicular dendritic cells
- present that antigen to helper T cells
- those survive
