Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Immunology > CH. 16 Autoimmune Diseases > Flashcards

CH. 16 Autoimmune Diseases Flashcards

1
Q

What is central tolerance?

A

-deletion of lymphocytes in primary lymphoid organs before they mature; limits development of autoreactive T- and B-cells

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

During central tolerance, B cells have been shown to undergo

A

receptor editing

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

Peripheral tolerance

A

either renders self-reactive lymphocytes nonresponsive (anergic) or actively generates inhibiting lymphocytes outside the BM and thymus; regulates autoreactive cells in circulation

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

Dependent mechanisms of CD4+ T cells

A
  • occur as TREG cells express high levels of inhibitory CTLA-4 molecules
  • CTLA-4 blocks CD28 activation through CD80/86, inhibiting APC activation/licensing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Independent mechanisms of CD4+ T cells

A

rely upon secretion of cytokines (IL-10, TGF-B, IL-35) into the surrounding area, shutting down nearby cell responses
-these mechanisms halt costimulation and activate indoleamine 2,3-dioxygenase, responsible for cleaving tryptophan, creates kynurenines, which inhibits T cells

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

In what ways do CD4+ T cells maintain tolerance?

A

work via contact dependent and independent mechanisms

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

What current mechanisms are anticipated to allow regulatory CD8+ T cells to maintain tolerance?

A
  • not likely generated in the thymus, but instead in the periphery during CD8+ T-cell activation induction events (appear after Ag-MHC class I stimulation in the presence of TGF-B)
  • Most likely use a range of mechanisms to suppress activity (lysis of APCs, inhibition of APC function, regulation of effector cells that bind the same Ag)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What factors can predispose an individual for tolerance rather than stimulation?

A
  • high doses of antigen
  • long-term persistence of antigen in the host
  • intravenous or oral introduction
  • absence of adjuvants
  • low levels of costimulation
  • presentation of antigen by immature or unactivated APCs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What percentage of people in industrialized countries are estimated to have an autoimmune disease?

A

3-8%

  • caused by failure of tolerance processes
  • may be organ-specific or systemic
  • may involve antibodies, T cells, immune complexes, or any combination of elements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What factors predispose an individual for developing an autoimmune disease?

A
  • studies have linked sex hormones to gene expression changes that could help explain why women experience autoimmune diseases more frequently
  • intrinsic and extrinsic factors can favor susceptibility to autoimmune disease
  • The roles of genes in susceptibility to autoimmunity (certain MHC genes linked to specific autoimmune disorders)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In most organ-specific autoimmunities, what four areas are treatments aimed at?

A
  • increasing levels of missing, required gene products (thyroid hormone, insulin, acetylcholine)
  • decreasing antibody production (B cell inhibitors)
  • decreasing inflammatory mediators (TNA, IL inhibitors)
  • decreasing costimulatory signals (CD80/86 inhibitors)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What potential side effects are affiliated with long-term use?

A
  • general toxicity, often to rapidly dividing cells (hair follicles, intestinal lining, blood cells)
  • also predisposes individuals to uncontrolled infections
  • can promote development of cancer by removing anti-tumor T and NK cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the holy grail of immunotherapy in treating autoimmunity?

A

Antigen-specific immunotherapy

stimulate tolerance to the auto-Ag, restoring balance

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

What is an example of the holy grail of immunotherapy in treating autoimmunity?

A

glatiramer acetate has been used to treat MS

  • four basic AAs found in mylein basic protein
  • selectively increases TREG cells, modulating APC function
  • although shifts T cell populations, it has shown only modest improvement over standard therapies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the four types of tissue transplantations?

A
  • autograft
  • isograft
  • allograft
  • xenograft
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Autograft

A

transplant from the same individual

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

Isograft

A

tissue transplant from genetically identical sibling or clone

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

Allograft

A

transplant from genetically different member of the same species

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

Xenograft

A

transplant from different species

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

First-set rejection

A

complete by 12-14 days, but memory of the anti-graft response is generated; first exposure

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

Second-set rejection

A

occurs much faster, completing within only 5-6 days; secondary immune iresponse

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

What is the role of T cells in graft rejection

A

T cells mediate graft rejection

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

Which type of T cells facilitate rejection?

A

-CD4+ more important, but CD8+ does too

24
Q

Histocompatible

A

tissues that are antigenically similar

25
How do you determine MHC compatibility?
Cross-matching
26
What allows organ transplant between completely mismatched people?
anti-rejection drugs (immunosuppressants)
27
Sensitization Stage of Graft Rejection
CD4 and CD8 cells recognize alloantigens expressed on foreign graft cells - T cells proliferate in response - May recognize donor MHC molecules directly - may recognize peptides from donor MHCs presented in the recipient's own APC MHC molecules (indirect) - Memory T cells generated
28
Effector Stage of Graft Rejection
- generally involves heavy infiltration of recipient cells into graft tissue (similar to DTH reaction) - can rarely involve production of Abs against donor HLA molecules or endothelial Ag
29
Hyperacute rejection
- by preexisting antibodies - occurs before grafted tissue ever revascularizes - antibodies bind to graft cells and activate complement - complete rejection may occur in as few as 24 hours
30
Acute rejection
- mediated by T-cell responses - begin 7-10 days post-transplantation - induce massive infiltration of lymphocytes and macrophages - rejection occurs through mechanisms described for effector stage of graft rejection
31
Chronic rejection
- develops months or years after acute rejection reactions have subsided - mechanisms include humoral and cell-mediated recipient responses - anti-rejection drugs help, but are not perfect
32
Total lymphoid irradiation
-used to eliminate lymphocytes -lymphocytes extremely sensitive to x-rays often used in bone marrow transplants or to treat GvHD -repeated x-ray exposures to the thymus, spleen, and lymph nodes -effectively wipes out the recipient's own immune cells, creating a situation where donor stem cells can engraft and form a "new" immune system safely
33
Azathioprine
- mitotic inhibitor that diminishes B- and T-cell proliferation - can dramatically increase survival rates of allografts by inhibiting proliferation of these cells - often prescribed with corticosteroids to prevent inflammation
34
Cyclophosphamide
inserts into DNA helix, disrupting it
35
Cyclosporin A (CsA)
- fungal metabolite - acts to decrease synthesis of inflammatory cytokines by preventing the activation of key transcription factors - not without side effects, including kidney toxicity
36
In Hashimoto's Thyroiditis, what is produced?
autoantibodies and sensitized TH1 cells specific for thyroid antigen
37
What do autoantibodies produced in Hashimoto's Thyroiditis do?
interfere with iodine uptake by thyroid, which decreases production of thyroid hormone. This results in hypothyroidism
38
In Hashimoto's Thyroiditis, a delayed-type hypersensitivity reaction occurs which results in:
inflammation --> goiter
39
Functions of thyroid hormone
- controls basal metabolic rate - protein synthesis - sensitivity to other hormones
40
What causes Type 1 Diabetes?
autoimmune attack against insulin-producing Beta cells in the pancreas
41
Type 1 Diabetes: After CTLs infiltrate the pancreas and activate macrophages, what happens?
Followed by cytokine release and production of autoantibodies, which may activate complement or antibody-dependent cell-mediated toxicity activities by NK cells
42
In Myasthenia Gravis, what do autoantibodies do?
bind acetylcholiine receptors on motor end plates of muscles
43
In Myasthenia Gravis, the binding of autoantibodies on acetylcholine receptors induces:
complement-mediated lysis of cells
44
In SLE, what kinds of autoantibodies are produced?
autoantibodies against DNA, histones, platelets, and other self structures
45
symptoms of SLE
- fever - weakness - kidney dysfunction - frequent skin rashes
46
in SLE, autoantibodies against RBCs and platelets induce
complement-mediated lysis
47
In SLE, autoantibodies against nuclear antibodies can deposit on walls of small blood vessels resulting in:
type III hypersensitivity reaction
48
In MS, autoreactive T cells form:
inflammatory lesions along myelin sheaths around nerve fibers in the brain and spinal cord
49
Breakdown of myelin sheaths around nerves leads to a range of symptoms:
numbness to paralysis and loss of vision
50
What virus may predispose a person to MS?
Epstein-Barr virus
51
What factors may predispose a person to MS?
- Epstein-Barr virus - hygiene hypothesis - sunlight exposure
52
_______ is a known immune modulator that promotes anti-nflammatory response.
Vitamin D
53
What is the major symptom of Rheumatorid arthritis?
chronic inflammation in joints
54
In rheumatoid arthritis, autoantibodies are reactive with:
determinants in the Fc region of IgG
55
Rehumatoid factos are often produced in rheumatoid arthritis and form _____ complexes and activate complement cascades.
immune

Immunology (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions