Brainscape's Knowledge GenomeTM

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


See full index

Immunology > Lecture 24: Tolerance and Autoimmunity I > Flashcards

Lecture 24: Tolerance and Autoimmunity I Flashcards

1
Q

Immune tolerance

A

State of specific unresponsiveness to an antigen induced by prior exposure to that antigen

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

Why is tolerance important

A

Immune cells don’t attack self cells

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

How does immune system address reactivity to self

A

2 ways:
1. Central tolerance-elimination of self reactive T cells in thymus
2. Peripheral tolerance- failure to provide signals to induce T cell response

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

What is central tolerance

A

Elimination of self reactive T cells in the thymus

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

What is peripheral tolerance

A

Failure to provide signals to induce a T cell response

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

Anergy

A

Programmed nonresponsiveness

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

Negative selection

A

Elimination of T cells that bind strongly with self in thymus

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

Positive selection

A

Elimination of T cells that don’t bind or weakly bind to self-MHC

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

What is AIRE- autoimmune regulator

A

A transcription factor that facilitates expression of non-thymus proteins in thymus to test reactivity

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

What is clonal anergy

A

Initiated when T cells are exposed to antigen in absence of co-stimulation

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

What is the mechanism of suppression in peripheral tolerance

A

Suppress NFKB, decreased production of IL-2, decreased T cell production

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

What is immune paralysis

A

High dose of antigen that bypass APC’s bind TCR’s directly, lack of co-stimulation, induce paralysis

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

How does antigen dose affect induction of tolerance

A

Very low doses of antigen fail to send sufficient signal, inadequate co-stimulation (tolerance)

Moderate doses=immune response (antibody production)

High doses can overstimulate the cells and initiate peripheral tolerance (immune paralysis)

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

Where does B cell central tolerance occur

A

Bone marrow once B cells express IgM

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

Where does B cell peripheral tolerance occur

A

Secondary lymphoid organs

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

What is central tolerance of B cells

A

Immature B cell exposed to low doses of antigen will cause clonal abortion

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

What is peripheral tolerance in B cells

A

Mature B cell undergoes one of the following: exhaustive antigen challenge, absence of co-stimulation, excessive suppressor cell, excessive T-independent

Results in functional deletion and receptor blockade

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

If an antigen is eliminated tolerance ___

A

Subsides

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

If an antigen persists, tolerance ___

A

Persists

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

Bone marrow activity (production of new cells) ___ tolerance

A

Reduces

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

Immunosuppressive drugs ___ tolerance

A

Prolong

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

In general, ___ drive immune response and ___ turn it off

A

Antigens, antibodies

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

Antibodies have a feedback loop on B cells to inhibit

A

Further production of antibodies

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

____ antibodies inhibit antibody production in newborn

A

Maternal antibodies (clinical relevant for timing vaccines)

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

What are some mechanisms of immune control

A

Antigen, antibody, inhibitory receptors, regulatory cells

26
Q

What is the result of inadequate immune response

A

Immunodeficiency, susceptibility to infections

27
Q

What is the result of an excessive immune response

A

Allergy, autoimmunity

28
Q

Adaptive immune responses are ___ driven

A

Antigen

29
Q

The effect of an antigen can be modulated by ___

A

Adjuvants

30
Q

What Ig does IgM suppress

A

IgM

31
Q

What Ig does IgG suppress

A

IgG and IgM

32
Q

What is the mechanism of suppression for antibodies

A

Inhibitory B cell receptor CD32B

33
Q

How does abnormally high antibody concentrations impact normal antibody synthesis

A

Inhibits normal Ab synthesis which leads to increased susceptibility to infection

34
Q

What receptor regulates the half life of IgG and albumin

A

FcRN

35
Q

What is the role of inhibitory receptors

A

Inactive or eliminate pathways that are no longer needed, suppress activity of lymphocytes when mission is accomplished

36
Q

What is the specific mechanism of action of CD32b

A

Negative feedback that suppresses B cell activation by cross linking BCR and Ab bound to CD32 with antigen

37
Q

What cell is responsible for maintaining homeostasis of peripheral immunity and tolerance

A

Tregs

38
Q

What immunosuppressive cytokines do Tregs produce

A

IL-10, Il-35 and TGF-B

39
Q

Treg deficiency results in

A

Multisystemic autoimmunity and massive inflammation

40
Q

What factors make up Treg

A

CD4+ CD25+FoxP3+ T lymphocytes

41
Q

What is FoxP3

A

Specialized transcription factor in generation of Treg cells

42
Q

What are the Tregs in cattle made of

A

WC1.1 + WC1.2 + gamma/delta T cells

43
Q

What are tTregs

A

Tregs that naturally originate in the thymus

44
Q

What are pTregs

A

Tregs that are induced in secondary lymphoid tissue

45
Q

What 3 signaling molecules are needed to induce pTregs

A

IL-2, RA, and TGF-B

46
Q

What cells do Tregs suppress

A

T cells and macrophages

47
Q

What are the three ways in which Tregs can suppress the immune system

A
  1. Direct contact
  2. Suppressive molecules
  3. Interference with antigen presentation
48
Q

Direct contact Treg suppression causes release of what molecules

A

TFG-B, perforins and granzymes, Galectin 1, CTLA-4, and TRAIL

49
Q

What does Galectin do

A

Induces cell cycle arrest in effector T cells

50
Q

What does CTLA-4 do

A

Induces apoptosis in effector cells

51
Q

What suppressive molecules are released from Tregs

A

IL-10, TGF-B, IL-35 and PGE2

52
Q

What molecules are secreted during interference with antigen presentation

A

Neuropilin 1
IDO

53
Q

What are the functions of IL-10

A

Suppress macrophages, suppress Th1 cells, supress Th2 cells, enhance Tregs, suppress Th17 production, supress NK cells, supress DC’s

54
Q

What is the function of TGF-B

A

Regulate T cell activiation, regulate macrophages, regulate B cell function

55
Q

What are the 2 regulatory macrophages

A

M1 and M2

56
Q

How are M1 and M2 activated

A

M1- classically activated
M2- activated by IL-4 and IL-13

57
Q

What does activation of M2 result in

A

Induction of tolerance, suppression of inflammation, tissue repair and angiogenesis, produce IL-4, IL-13, IL-10 and TGF-B

58
Q

What does indoleamine 2,3 dioxygenase do

A

Tryptophan depletion and cell cycle arrest

59
Q

What IL is involved in tissue healing

A

IL-22

60
Q

What are the functions of IL-17

A

Induce growth factors, stimulates Th cells, mobilizes neutrophils, stimulate epithelial cells, stimulates macrophages

61
Q

What happens if the mechanisms that regulate tolerance fail?

A

Autoimmune disease

62
Q

Autoimmune disease

A

Disease resulting from an attack by an individuals immune system against that individuals own tissues

Immunology (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions