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SP14 Microbiology > EX1 Tolerance/Autoimmune Disease - Powell > Flashcards

EX1 Tolerance/Autoimmune Disease - Powell Flashcards

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Biology 101 flashcards
1
Q

physiological state in which the immune system does not react destructively against self tissues; it is LEARNED

A

self-tolerance

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2
Q

occurs in generative lymphoid organs (bone marrow/thymus) involving immature self-reactive lymphocytes encountering self antigen

A

central tolerance

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3
Q

in peripheral sites involving mature self-reactive lymphocytes encountering self antigen

A

peripheral tolerance

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4
Q

True or False

Tolerance is simply a failure to recognize an antigen

A

False; tolerance is an active response and is just as specific as an immune response

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5
Q

Tolerance can be _______ or _______

A

natural

induced

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6
Q

The most important aspect of tolerance is _____ ______; which prevents the body from mounting an immune attach against its _____ ______

A

self tolerance

self tissues

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7
Q

Immature T cells that recognize antigens with _____ _____ are deleted and some some reactive _____ T cells that see self antigens in the thymus are not deleted but instead differentiate into ________ ___ ____

A

high avidity
CD4
regulatory T cells

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8
Q

The choice between lymphocyte activation and tolerance is determined by;
the properties of the ________
state of ______ of the antigen-specific lymphocytes
types of _______ received when these lymphocytes encounter _____ _____

A

antigen
maturation
stimuli
self antigens

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9
Q

Central tolerance of B cells occurs the ___ _____; potentially auto reactive cells can be ______ or ______ by contact with _____ antigens

A

bone marrow
eliminated
inactivated
self

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10
Q

Central tolerance of B cells is achieved via _______ editing

A

receptor

VDJ rearrangement

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11
Q

______ and ________ of the self antigens determine the fate of B cells

A

nature and concentration

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12
Q

True or False

multivalent and high concentrations of antigens induce B cell death

A

True; lower concentrations induce functional anergy

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13
Q

_______ _______ is the mechanism by which mature T cells that recognize self antigens in peripheral tissues become incapable of responding to these antigens

A

peripheral tolerance (PT)

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14
Q

Mechanism of PT; actual elimination from the cellular repertoire by activation induced cell death

A

clonal deletion/apoptosis

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15
Q

Mechanism of PT; mature cell is present but its functionally inactivated (can be reserved)

A

clonal anergy

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16
Q

Mechanism of PT; inhibition of cellular activity through interaction with other cell (T-regs, etc.)

A

suppression

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17
Q

Mechanism of PT; coexistence of self-reactive clones and antigen; cells do not respond to antigen

A

ignorance

18
Q

Factors determining which mechanisms are operative;
________ of self antigen in lymphoid organs
________ of antigen receptor for antigen
______ of the antigen
concentration and availability of _____ molecules

A

concentration
affinity
nature
co-stimulatory

19
Q

True or False
Peripheral tolerance in B cells; NOT all potentially reactive cells are eliminated or inactivated and enter peripheral circulation

A

True

20
Q

T cells affect the outcome of B cell activation in the periphery via the ____ _____ ____

A

two signal hypothesis

21
Q

What are the two signals of the two signal hypothesis

A
  1. generated through the antigen receptor

2. mediated by CD40 and CD40L

22
Q

If one of the signals from the two signal hypothesis is missing B cell ______ occurs

A

anergy (lack of reaction to the antigen)

23
Q

Anergic cells show a block in _____ ____ signal induction; via lack of co-stimulation by _______ and co-stimulation by ____ _____

A

TCR-induced
B7/B72
inhibitory receptors

24
Q

________ competes with CD28 for B7 and B72; it helps to keep the T cells in check

A

CTLA-4 (is an inhibitory receptor on T cells)

25
Q

Knockout mice lacking CTLA-4 develop ______ lymphocyte activation, ______ lymph nodes and spleen, and ______ multi organ lymphocytic infiltrates

A

uncontrolled
enlarged
fatal

26
Q

Self-reactive cells may be “deleted” from the repertoire via __________; activation in the absence of _____ can lead to death

A

apoptosis

IL-2

27
Q

The state of tolerance may be maintained by ____ _____

A

immune regulation

28
Q

How does ignorance happen;
antigen is expressed in a ______ _____
T cells cannot get to the antigen across an ______ _______
perhaps the antigen is not expressed in the context of ______ _____

A

immuno-privileged site
epithelial barrier
MHC molecules

29
Q

Foreign antigens may be administered in ways that preferentially _____ _____ rather than immune responses

A

induce tolerance

30
Q

True or False
Oral administration of antigen favors tolerance induction; a state of immune hypo responsiveness follows oral administration of an antigen

A

True

31
Q

Five factors that lead to immunogeneicity or tolerogenicity of protein antigens include…

A 
amount
persistance
portal of entry/location
persistence of adjuvants
properties of APCs
32
Q

True or False

Mechanisms that lead to autoimmunity remain unclear

A

True

33
Q

Seven factors can predispose an individual to various autoimmune diseases….

A 
MHC associateions
familial concordance (occurs in families)
gender (women more likely than men)
climate (equatorial less likely)
chemical agents
infectious agents
immune dysregulation
34
Q

What 3 things involving self-reactive cells initiates an autoimmune response

A

incomplete deletion
aberrant stimulation
altered regulation

35
Q

True or False

Autoimmune disease can be systemic or organ specific

A

True

36
Q

“Bystander activation” involves the induction of co-stimulators on ________ via up regulation of ________ resulting in autoimmunity

A

APCs

B7

37
Q

_______ _______ results in a microbial antigen imitating a self tissue causing autoimmunity; this is more likely the case

A

molecular mimicry

38
Q

An example of a systemic autoimmune disease is _____ and an example of organ specific autoimmune disease is _____

A 
systemic lupus erythematosus (SLE) - kidney, heart, lungs, CNS
multiple sclerosis (MS) - CNS
39
Q

SLE produces _________ against self antigens such as DNA, nucleoproteins, lymphocytes, etc

A

autoantibodies

40
Q

In MS, T cells are specific for components of the _____ ______

A

myelin sheath

SP14 Microbiology (31 decks)

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