T cell antigen recognition T cell activation

Question 1

L selectin is expressed by naive T cells and binds to

Answer 1

CD34//GLYCam-1

Question 2

LFA-1 binds to

Answer 2

ICAM1 on HEV for the adhesion to the HEV

Question 3

T cell to APC cell use what adhesion molecule interactions? LFA-1, CD2, and ICAM3

Answer 3

LFA-1 –> ICAM1 or 2, CD2–> LFA3, ICAM3-LFA1

Question 4

Dendritic cells are most efficient to present

Answer 4

viral peptide antigens/ extracellular

Question 5

Macrophages are most efficient for presentation of

Answer 5

extracellular, independently replicating organisms (Bacteria/yeast) can also present intracellular antigens

Question 6

B cells most efficiently present peptide from

Answer 6

soluble antigens (intracellular and extracellular antigens)

Question 7

Antigen presenting cells (APCS) express a costimulator molecule

Answer 7

B7

Question 8

B7 binds to (on APC)

Answer 8

CD28 (on the T cells)

Question 9

two signals for activation of T cells

Answer 9

1. binding of its TCR to cognate peptide on MHC

2. co stimulation of B7 (APC) to CD28 (T Cell)

Question 10

Immature dendritic cells function is to

Answer 10

take up antigen (Mature dendritic cells no longer take up antigen)

Question 11

Mature dendritic cells express co stimulatory molecules

Answer 11

B7.1 and B7.2 and high levels of MHC class I and II molecules

Question 12

Mature dendritic cells express what adhesion molecules?

Answer 12

ICAM1, ICAM2, LFA1, LFA3

Question 13

Dendritic cells also express a chemotactic cytokine that attracts naive T cells

Answer 13

DC-CK

Question 14

resting macrophages express very low levels of ? and do not express?

Answer 14

low levels of MHC class II and low levels of B7!

Question 15

Without a costimulation signal, the macrophages induce anergy, a process called

Answer 15

peripheral tolerance

Question 16

Once ingest microorganisms, macrophages will up regulate their expression of what molecules?

Answer 16

MHC Class II and B7

Question 17

B cells activation process

Answer 17

1. BCR binds to soluble antigen, produces activation signal

2. B cell internalizes and process antigen, presents peptides on MHC Class II molecules

Question 18

B cells readily present antigen to antigen specific

Answer 18

CD4 T cells, T cells will produce 2nd signal of activation if they are effector T cells

Question 19

T cell activation signals

Answer 19

1. encounter with specific peptide antigen bound to an MHC molecule on APC
2. CD28 on T cell interaction with FB7 on APC

Question 20

Signaling of CD28 and B7, increases/stabilizes/upregulates

Answer 20

IL-2

Question 21

T cell that recognizes specific antigen bound to MHC, but has no costimulation signal will become

Answer 21

anergic, peripheral tolerance

Question 22

CD8 T cells must be activated by

Answer 22

dendritic cells

Question 23

Produced by activated T cells upon activation

Answer 23

IL-2

Question 24

Which IL can promote T cell proliferation? and promotes differentiation into armed effector T cells?

Answer 24

IL-2

Question 25

Moderate affinity IL-2 receptor has what chains?

Answer 25

beta, gamma

Question 26

when resting T cell encountered specific antigen, it produces IL2 and

Answer 26

alpha chain of IL2 receptor

Question 27

Armed effector T cells do not require what?

Answer 27

costimulation signal (B7: CD28)

Question 28

Armed effector T cells express high levels of which adhesion molecules?

Answer 28

LFA-1, CD2, VLA-4

Question 29

TH1 CD4 cells are primarily involved with recognizing MHC Class II molecules on

Answer 29

macrophages and b cells

Question 30

CD8 T cells recognize peptide antigens on

Answer 30

MHC Class I

Question 31

TH2 CD4 cells recognize peptide antigens bound to

Answer 31

MHC Class II on B cells

Question 32

Which T cell promotes class switching and somatic hypermutation ?

Answer 32

TH2 CD4: induce B cells to produce other isotopes of Ab

Question 33

What do TH1 CD4 t cells induce B cells to

Answer 33

produce Ab that are efficient for opsonization (IgG1 and IgG3)

Question 34

What cytokines usually cause CD4 Th0 cells to become TH1

Answer 34

IL-12, IFN-gamma

Question 35

IL-12 is produced by ? and when?

Answer 35

macrophages and dendritic cells in response to viral and some intracellular bacterial infections

Question 36

NK cells produce IFN-gamma for?

Answer 36

to inhibit development of TH2 cells

Question 37

CD4 TH0 activated to become TH2 in presence of what?

Answer 37

IL-4, 5, 6

Question 38

Which cytokines inhibit generation of TH1

Answer 38

IL-4, IL-10

Question 39

TH2 cells produce what? inactivates growth of TH1

Answer 39

IL-10, TGF-beta

Question 40

Self antigen specific T cell receptors can be found on what?

Answer 40

regulatory T cells

Question 41

What surface protein is found on Tregs?

Answer 41

CD25

Question 42

Tregs express a transcriptional repressor known as

Answer 42

FoxP3

Question 43

In presence of TGF-beta, TH0 differentiate into

Answer 43

Tregs

Question 44

Tregs recognize

Answer 44

self-determinants

Question 45

IPEX (immune dysregulation, polyendocrinopathy, enteropathy, x linked syndrome) deficiency in

Answer 45

FoxP3

Question 46

Th17 produce what interleukins?

Answer 46

IL-17, IL-21, IL-22

Question 47

TH17 promote what influx?

Answer 47

neutrophil

Question 48

deficiency of Th17 cells can leave patient susceptible to

Answer 48

opportunistic pathogens

Question 49

VLA-4 is an integrin on surface of EFFECTOR t cells that binds to

Answer 49

VCAM-1 of activated vascular endothelial cells for transmigration of effector T cells out of vasculature

Question 50

lower than normal levels of IgM but almost undetectable quantities of IgG or IgA in serum. lymph biopsy reveals near total lack of germinal center formation. Non-sense mutation of?

Answer 50

IL-2. Normal numbers of B cells and T cells. B cells appear to be functional because of IgM. Defect that prevents him from mounting CD8 or CD4 mediated immune responses. IL-2 is required for proliferation and differentiation after activation. Patients with this defect can't make CD4 or CD8 T cell response, can't activate B cells

Question 51

IL-4 deficient patient, more susceptible to?

Answer 51

extracellular pathogens

Question 52

IL-12, IFN-gamma deficient patient more susceptible to?

Answer 52

intracellular pathogens (no TH1 response)

Question 53

Heightened susceptibility to viral, bacterial, fungal pathogens. SCID. elevated serum concentrations of IgM, but almost undetectable concentrations of other antibodies. normal levels of all immune cells in circulation. Normal architecture, except total lack of germinal centers Clinical history shows what?

Answer 53

Lack of B7 expression on macrophages and dendritic cells isolated from secondary lymphoid tissues. No ability to produce B7, unable to activate T cells (CD4 and CD8). SCID patients.

Question 54

Deficiency in VCAM-1 or VLA4 would prevent effector T cells from what?

Answer 54

migrating from circulation into inflammatory sites.

Question 55

GATA3 drives transcription of cytokines by

Answer 55

Thelper 2 type effector CD4 T cells. (heightened susceptibility to extracellular pathogens)

Question 56

T-bet drives expression of cytokines by

Answer 56

T helper type 1 cells. (heightened susceptibility to intracellular pathogens)

Question 57

Thelper17 cells produce? what does this do?

Answer 57

IL-17, IL-22 that promotes production of antimicrobial peptide/proteins by epithelial cells

Question 58

Most important immune response for clearance of most viral infections is an acquired response that allows for high specificity detection and killing of virally-infected cells early in replicative cycle. What is this?

Answer 58

Cytotoxic T lymphocytes are effectors of this response. | T helper 1 type T cells are next because they produce cytokines that activate CD8 t cells.

Question 59

What type of antigen presentation would be expected with someone that has inflamed laceration of right arm and white exudate (pus)?

Answer 59

PUS: rules out viral infection and intracellular bacterium. Extracellular: pathogen would be via MHC class II pathway. CD4 cells. B cells and dendritic cells can take up bacterial, but macrophages take them up much more efficiently. B cells would have to have a BCR that has specificity for that single pathogen.

Question 60

Highly prone to activate self-reactive T cells, variety of autoimmune conditions developed. most likely cause?

Answer 60

Lack of T reg cell functionality. self-reactive effector CD4 T cells subset. Recognize cognate peptide determinant, produce anti-inflammatory cytokine TGF-beta that acts on nearly T cells that prevents from being activated (prevents activation of self-reactive T cells). FoxP3 drives expression of TGF-beta by Treg cells.

Question 61

GATA-3 drives cytokine expression by

Answer 61

TH2 effector cells

Question 62

T-bet transcription factors drive cytokine expression by

Answer 62

TH1 effector cells.