L14-15

Question 1

Th0

Answer 1

precursor to Th1, Th2, Th17

Question 2

Th1

Answer 2

cell-mediated immune response

Question 3

Th2

Answer 3

antibody mediated immune response

Question 4

CD44

Answer 4

adhesion molecules that helps home lymphoid progenitor cells from the bone marrow to the thymus, along with chemokines

Question 5

RAG-1, RAG-2

Answer 5

expressed by the lymphoid precursors one they have entered the thymic cortex, responsible for rearranging beta chain genes of the TCR

Question 6

Pre-T cell surface molecules

Answer 6

beta chain, pre-Talpha, CD3, and zeta chain to make up the pre-TCR

Question 7

Thymocyte surface molecules

Answer 7

rearranged alpha and beta chains, CD4 AND CD8, CD3

Question 8

Double positive cell

Answer 8

thymocyte that expresses both CD4 and CD8

Question 9

Positive selection of thymocytes

Answer 9

in thymic cortex, epithelial cells expressing both HLA I and II bind CD4 and CD8 with a critical affinity, too much or too little results in apoptosis

Question 10

positive selection results in

Answer 10

thymocytes with HLA-restriction or educated thymocytes that respond only to “self” HLA + antigen, capable of autoimmunity

Question 11

Negative selection of thymocytes

Answer 11

dendritic cells at the cortico-medullary junction weeds out self-reactive T cells through apoptosis or T cell anergy

Question 12

Negative selection results in

Answer 12

thymocytes that are self-tolerant

Question 13

Mature T cells possess

Answer 13

alpha/beta TCR, CD3, and CD4 or CD8, self-HLA restricted, self-tolerant, foreign antigenic peptide specific

Question 14

What T cells develop independent of thymus?

Answer 14

gamma/delta TCR T cells, not HLA-restricted, do not possess CD4 or CD8

Question 15

Activation of naive T cells begins when

Answer 15

A-laden dendritic cells migrate to lymph nodes from tissues through HEV and act as APC

Question 16

CCL21

Answer 16

chemokine produced by epithelial cells to help home naive T cells to HEV with APC

Question 17

CCL18

Answer 17

chemokine produced by dendritic cells to help home naive T cells to HEV with APC

Question 18

T cell activatio occurs when

Answer 18

they recognized self HLA-antigen complex

Question 19

lymphoblast

Answer 19

activated enlarged T lymphocytes

Question 20

T cell function

Answer 20

deal with intracellular antigens, produce cytokines, cytotoxicity

Question 21

TCR

Answer 21

alpha-beta heterodimer with variable regions (Valpha and Vbeta) to form the Ag binding site

Question 22

CD-3

Answer 22

T cell specific: chaperone for TCR to the cell surface, cellular signaling molecule

Question 23

zeta chains

Answer 23

not T cell specific, mostly intracellular and associated with CD3, involved in signaling

Question 24

ITAMs

Answer 24

immunoreceptor tyrosine-based activation motifs: sets off activation cascade of events

Question 25

CD4+ activation causes transcription of

Answer 25

IL-2 and IL-2R

Question 26

IL-2

Answer 26

acts as a growth factor and causes lymphoblasts to enter G1

Question 27

effector T cell

Answer 27

influence the adaptive immune response by producing cytokines

Question 28

memory cells

Answer 28

fewer activation requirements

Question 29

Co-receptors

Answer 29

CD4 and CD8, mutually exclusive in MATURE lymphocytes; adhesion molecules and signal transducers

Question 30

B7

Answer 30

APC accessory molecule necessary to activate naive T cells

Question 31

CD 28

Answer 31

T cell accessory molecule necessary to activate naive T cells

Question 32

Th0

Answer 32

precursor to Th1, Th2, Th17; produce IL-2, IL-4, and IFN-gamma

Question 33

Th1 produces

Answer 33

IL-2 and IFN-gamma

Question 34

What cytokines promote Th1 differentiation

Answer 34

IL-12 (APC) and IFN-gamma (NK cells)

Question 35

Th1 function

Answer 35

cell-mediated type 1 response, activation of NK cells, CTL, macrophages, Th1, B cell isotope switch to IgG3

Question 36

Th2 produces

Answer 36

IL-4, IL-5, IL-10, IL-13

Question 37

What cytokines promote Th2 differentiation

Answer 37

IL-4 (mast cell, NK cell, dendritic cell)

Question 38

Th2 function

Answer 38

humoral immune response type 2, B cell isotope switch to IgG1, IgG2, IgG4, IgA, IgE, activate Th2, recruit granulocytes

Question 39

Th17 produces

Answer 39

IL-17, IL-21, IL-22

Question 40

What cytokines promote Th17 differentiation

Answer 40

IL-6, IL1beta, IL-23 (APC)

Question 41

Th17 function

Answer 41

autoimmune response, increased neutrophil production

Question 42

Treg produces

Answer 42

TGF-beta, IL-10, IL-4

Question 43

What cytokines promote Treg differentiation

Answer 43

CD25 and FoxP3

Question 44

Examples of diseases resolving from Th1

Answer 44

TB, chlamydia, IC parasites, and HIV

Question 45

Examples of diseases resolving from Th2

Answer 45

pneumococcal, pneumonia, diptheria, helminthic parasites, meningococcal

Question 46

Th1 responses can cause diseases

Answer 46

silicosis, delayed hypersensitivities, contact hypersensitivities, TB leprosy

Question 47

Th2 responses can cause diseases

Answer 47

asthma, allergies, systemic lupus erythematosis, lepromatous leprosy

Question 48

Th 17 responses can cause disease

Answer 48

RA, MS, psoriasis

Question 49

What is required for activation of CTL effectors

Answer 49

IL-2 (Th0) from neighboring active CTLs and co-stimulation of CD28

Question 50

Granule mediated killing

Answer 50

cytoplasmic granules from CTL effector cells are exocytosed directly onto cell membrane (perforin, granzymes, cytokines, fragmentin)

Question 51

perforin

Answer 51

in CTL granules, polymerizes with Ca on cell membrane to form channels, increase cell permeability and eventually lead to cell death (similar to C9)

Question 52

Cytokines within CTL granules:

Answer 52

TNF-beta (lymphotoxin), TNF-alpha

Question 53

Granzymes within CTL granules

Answer 53

enzymes that play a role in cell lysis

Question 54

Fragmentin

Answer 54

granzyme enzyme that causes DNA fragmentation and causes apoptosis

Question 55

Fas-FasL CTL killing mechanism

Answer 55

FasL on CTL binds Fas on APC, caspases induce apoptosis of target cell

Question 56

NK cells are

Answer 56

CD16/CD56+, do not require APC, sensitization

Question 57

KIRs

Answer 57

killer cell inhibitor receptors: bind MHC molecules to prevent lysis, if MHC is down regulated, KIR doesn't bind and apoptosis occurs with perforins and granzymes

Question 58

NK activity is unregulated by

Answer 58

IL-2, IFN-gamma

Question 59

NK function

Answer 59

defense against tumors, first line of defense against intracellular infections

Question 60

ADCC

Answer 60

Killer cells that possess Fc receptors for IgG (NK, macrophages, eosinophils, neutrophils, and CTL)

Question 61

NK cell ADCC

Answer 61

CD16 binds IgG Fc molecules, then becomes cytotoxic

Question 62

Macrophage cytotoxicity

Answer 62

when activated by IFN-gamma, lysosomal contents are released or TNF-alpha is used to induce apoptosis, NO and ROS can be cytotoxic as well