Autoimmunity and Allergies (QUIZ 5) Flashcards

1
Q

What is autoimmunity

A

-Immune response to self-antigens leading to damage (congenital- mutations and acquired)
-Autoantigens, autoantibodies, autoreactive (T cells recognizing self)
-Prevented by self-tolerance (think B/T cells selection and central and peripheral)
-Autoimmunity is a failure of tolerance

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2
Q

What is the autoimmune regulator

A

AIRE, it up-regulates transcription of many genes in thymus

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3
Q

Deletion of AIRE leads to an autoimmunity targeting what

A

-mainly gladular tissues
-loss of AIRE leads to destruction of endocrine tissues (b/c these make a lot of specialized proteins no found anywhere else)

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4
Q

What disease does AIRE deficiency can lead to

A

Type I diabetes

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5
Q

What are the four sources of autoimmune

A

-Ignorant (aren’t active for some reason)
-Low-affinity (need a co-stimulatory signal)
-Anergic cells are non-responsive to antigen
-Other infections can activate them

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6
Q

What is an example of an infection activating autoimmune

A

-systemic lupus erythematosus
-Some B-cells can bind DNA (dsDNA)
-Damage to tissues releases high amounts of DNA (can overwhelm phagocytosis and can also activate B cells)
-Also can activate TLR (co-stimulatory signal)

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7
Q

A release of what components can activate an autoimmune response

A

-release of internal component (such as after a heart attack)
-internal components not always displayed (BCR only finds exposed epitopes)
-massice cell death can release them and then activate them

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8
Q

How is somatic hypermutation another source of an autoimmune response

A

-Somatic hypermutation can lead to generation of self-reactive Ab’s
-A B cell generated against an antigen
-then it mutates for higher affinity (accidently gains self-recognition)
-appears to be a way to kill these cells (apoptosis)

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9
Q

What two responses are required for autoimmune diseases

A

Requires both B and T cell responses

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10
Q

What is special about Grave’s Disease

A

-Shows that autoimmunity can cross the placenta
-Attacks the thyroid
-removes Ab’s through plasmapheresis

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11
Q

How is autoimmunity conditions temporary

A

-many end when the damage is gone
-there could be a cycle (damaged tissues activate autoimmunity and then autoimmune cells damage tissues)

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12
Q

What is epitope spreading

A

-development of autoimmune responses to epitopes beyond the initiating epitope (ex: BCR that uptakes DNA also takes up histone proteins, present them to T cells, and now responds to histone epitopes)`

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13
Q

What are Cryptic epitopes

A

-epitopes normally ‘hidden’ from the immune system now being expressed

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14
Q

What are the consequences of epitope spreading

A

-actually hard to answer
-used for diagnostic testing (presence of certain antibodies=different autoimmune diseases

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15
Q

What are the two methods of a few autoimmune diseases

A

-antibody (receptor binding and immune complexes)
-Cell-mediated (cytotoxic T cells)

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16
Q

What is Autoimmune hemolytic anemia

A

-the lysing of red blood cells
-the immune system attacks RBC’s
-antibodies bind antigen on RBC
-leads to complement activation (MAC formation)
-FcR’s and CR’s lead to RBC phagocytosis

17
Q

What is an antagonist antibody

A

-blocks signaling of pathways
-antibodies can bind receptors and block receptor function

18
Q

What is an agonist antibody

A

-activates receptors (opposite of antagonist)
-antibodies can bidn receptors and ACTIVATE receptor function

19
Q

What are many autoimmune pathologies caused by

A

-chronic inflammation
-Goodpasture’s syndrome (Ab against a type of collagen)
-binds to the basement membrane
0Recruits and activates immune system (attacks membranes and kidneys and lings specifically susceptible)

20
Q

What happens to immune complexes with autoimmune

A

-usually immune complexes are phagocytized, but with autoimmune, they are constantly being made

21
Q

What happens with complex formation

A

-degradation, they can cause damage
-example: mixed essential cryogloulinemia

22
Q

What is a common sign of autoimmune

A

-Rheumatoid factor (Ab against Ab)
-Ig that binds Fc of IgG, marker in many autoimmune diseases, ‘anti-antibodies’

23
Q

How do immune complexes cause damage

A

-they get stuck (in small vessels and joints)
-Vasculitis
-can induce inflammation

24
Q

What is an example of cytotoxic T cells in autoimmune

A

-type 1 diabetes

25
Q

What are autoantibodies

A

any antibody against self

26
Q

What are anti-antibodies

A

antibodies against antibodies