Exam 2- Immunologic Tolerance and Autoimmunity

Question 1

what is central T cell tolerance?

Answer 1

T cells that do not recognize self antigens or recognize self antigens with high affinity are deleted

Question 2

what prevents T cells from reacting with peripheral self-antigens?

Answer 2

peripheral T cell tolerance

Question 3

what leads to anergy of a T cell?

Answer 3

T cell recognizes antigens without adequate levels of costimulation

Question 4

what are the two mechanisms for deletion of T cells?

Answer 4

antigen recognition without costimulation
activation-induced cell death: Fas and Fas ligand

Question 5

what are CTLA-4 and PD-1?

Answer 5

inhibitory receptors

Question 6

true/false: binding of CTLA-4 on activated autoimmune T cells with B7 on APCs always leads to deletion of the T cells

Answer 6

false: inactivation

Question 7

true/false: if a cells expressing Fas binds with a cell expressing FalL, the cell expressing Fas dies by apoptosis

Answer 7

true

Question 8

what cytokines do T regulatory cells produce?

Answer 8

immunosuppressive cytokines TGF-beta and IL-10

Question 9

are T regulatory cells CD4+ or CD8+?

Answer 9

CD4+

Question 10

what is central B cell tolerance?

Answer 10

B cells that recognize self antigens with high affinity are deleted or they change their receptor specificity

Question 11

what does indolamine 2,3-dioxygnease (IDO) play a role in?

Answer 11

tolerance of an allogeneic fetus
inhibits alloreactive T cell proliferation through catabolizing tryptophan

Question 12

what is bystander activation?

Answer 12

infection of tissue may induce local innate immune response to the infection: more costimulators (B7) and cytokines by the tissue APCs

Question 13

what is molecular mimicry?

Answer 13

when a microorganism shares an epitope with a self antigen

Question 14

polyclonal lymphocyte activators: what does exposure to B cell mitogens such as bacterial lipopolysaccharide lead to?

Answer 14

activation large number of B cells

Question 15

what are immunologically privileged sites?

Answer 15

central nervous system, eyes, testes

Question 16

what genes are most commonly associated with autoimmunity?

Answer 16

MHC genes

Question 17

does Th17 play a larger role than Th1 in autoimmunity ever?

Answer 17

yes, not always

Question 18

true/false: infection by a virus which expresses one or more antigens that share antigenic identity with the self-antigens can lead to an autoimmune disease

Answer 18

true

Question 19

true/false: both hypothyroidism and hyperthyroidism are examples of autoimmune diseases

Answer 19

true, but hyperthyroidism more rare to be autoimmune

Question 20

true/false: serum antibodies against thyroid peroxidase enzyme can be detected in hyperthyroidism cases

Answer 20

true

Question 21

true/false: Th1 cells are always the most important adaptive immunity cell type in inducing inflammatory autoimmune disorders

Answer 21

false

Question 22

what antibodies are involved in epidemolysis bullosa acquisita?

Answer 22

IgA and IgG autoantibodies against anchoring fibrils of lower basement membrane: type VII collagen

Question 23

how are autoimmune diseases treated?

Answer 23

drugs, plasmapheresis, monoclonal antibody treatment

Question 24

what are the mechanisms of peripheral T cell tolerance?

Answer 24

anergy, deletion, or suppression of autoreactive T cells

Question 25

what are the costimulating agents for T cells?

Answer 25

B7 and CD28

Question 26

repeated activation leads to expression of ____________________________ on the surface of T cells

Answer 26

Fas (CD95) and Fas ligand (FasL)

Question 27

why is Fas called a death receptor?

Answer 27

the cell which expresses Fas and has a FasL bind to it will undergo apoptosis

Question 28

true/false: persistent high antigenic load in chronic viral infections or cancers lead to T cells upregulating inhibitory receptors

Answer 28

true

Question 29

do natural Treg cells survive negative selection in the thymus? are they autoreactive?

Answer 29

yes yes

Question 30

what cytokines do Treg cells produce after they become activated and differentiate?

Answer 30

immunosuppressive cytokines TGF-beta and IL-10

Question 31

what do the cytokines that Treg cells produce suppress?

Answer 31

lymphocyte and antigen presenting cell activity

Question 32

what is the mechanism of human leukocyte antigen-G (HLA-G)?

Answer 32

binds to inhibitory receptors on NK cells to prevent killing of target cells in fetus: do not express MHC molecules

Question 33

what does complement receptor 1-related protein y (Crry) do?

Answer 33

protects placental tissues from complement-mediated damage (classical pathway)

Question 34

what antigens does Trypanosoma cruzi share with mammals?

Answer 34

mammalian neurons and cardiac muscle

Question 35

what leads to systemic lupus erythematosus?

Answer 35

deficiency of C3, a non-MHC molecule

Question 36

what is the most common cause of blindness in horses?

Answer 36

equine recurrent uveitis

Question 37

what breed of dog has epidermolysis bullosa acquisita been identified in?

Answer 37

great dane