Effector Mechanisms of T Cell Mediated Immunity

Question 1

Th0 cell

Answer 1

Produces several various helper T subsets: Th1, Th2, Th17, Tfh.

Question 2

Th1 cells

Answer 2

Activate a cell-mediated immune response.

Question 3

Th2 cells

Answer 3

Activate an Ab-mediated immune response. Helminths and parasites.

Question 4

Th17 cells

Answer 4

Involved in inflammation and anti-bacterial response.

Question 5

Tfh cells

Answer 5

Remain in the LN and help B cells.

Question 6

Inducing cytokines of Treg:

Answer 6

IL-2 and TGF-beta.

Question 7

Cytokines produced by Treg (3):

Transcription factors of Treg cells (2)

Answer 7

TGF-beta
IL-10
IL-35

STAT6
FXP3

Question 8

Inducing cytokine of Th1:

Answer 8

IL-12

Question 9

Cytokines produced by Th1 (1):

Transcription factors of Th1 (2)

Answer 9

IFN-gamma

STAT4
T-bet

Question 10

Inducing cytokine of Th2:

Answer 10

IL-4

Question 11

Cytokines produced by Th2 (3):

Transcription factors of Th2 cells (2):

Answer 11

IL-4
IL-5
IL-13

STAT6
GATA3

Question 12

Inducing cytokines of Th17:

Answer 12

TGF-beta and IL-6

Question 13

Cytokines produced by Th17 (3):

Trancription factors of Th17 cells (3):

Answer 13

IL-17A
IL-17F
IL-22

CCL20
STAT3
RORyt

Question 14

Th1 , Th2 and Th17 are all:

Answer 14

CD4+ helper cells.

Question 15

TGF-beta function

Answer 15

Acts as an inhibitor/dampener of immune responses, but stimulates differentiation of Treg cells.

Question 16

Development of Th1 cells

Answer 16

STAT4 and T-bet produced via IL-12 and IFN-gamma from NK cells activates STAT1, which together stimulates differentiation of naive CD4+ cells.

Question 17

How does Th1 cells amplify their reproduction?

Answer 17

They produce IFN-gamma which inhibits the development of Th2 and Th17 cells.

Question 18

How do macrophages respond to activation?

Answer 18

Produce ROSs, NO, lysosomal enzymes.
Secretion of cytokines.
Increased expression of B7 and MHC molecules.

Question 19

IL-4 is produced by:

Answer 19

Mast cells and eosinophils.

Question 20

What stimulates the differentiation of naive CD4+ cells to the Th2 subset?

Answer 20

By activating GATA-3 and STAT6.

IL-4 can also amplify the response by inhibiting the development of Th1 and Th17 cells.

Question 21

Th1 activate _________, which can cause:

Answer 21

M1.
Microbactericidal actions (phagocytosis, killing, etc) and Inflammation.

Question 22

Th2 activate __________, which can cuase:

Answer 22

M2.

Anti-inflammatory effects.

Question 23

Development of Th17 cells

Answer 23

Activation o RORyt and STAT3 via IL-1, IL-6 and TGF-beta which cause differentiation of Th17 cells.

Question 24

IL-21 function in development of T17 cells:

Answer 24

It is induced by RORyt and STAT3 which amplifies generation of Th17 cells in an autocrine manner.

Question 25

TGF-beta promotes Th17 responses by:

Answer 25

Suppressing Th1 and Th2 cells.

Question 26

IL-23 can cause:

Answer 26

Activation of Th17 cells.

Question 27

IL-17 produced by Th17 cells...

Answer 27

Protects from extracellular pathogens and is involved in inflammation and autoimmunity.

Question 28

Increased IL-17/IL-22 induces:

Answer 28

Inflammation and neutrophil response.

Question 29

Constitutive levels of IL-17/IL-22 causes:

Answer 29

Homeostasis.

Question 30

Helper T cells are restricted to:

Answer 30

MHC II.

Question 31

CTLs are restricted to:

Answer 31

MHC I.

Question 32

Cross presentation of APCs:

Answer 32

Allows APCs to present extracellular Ags on MHC I.

Question 33

Which is generated first: CD4+ or CD8+?

Answer 33

CD4+

Question 34

Licensing of DCs

Answer 34

Occurs when the CD4+ cell delivers activating signal via CD40L/CD40 signaling and cytokines (IFN-gamma) to DC after it recognizes Ag presented by an MHC II APC.

Question 35

CD40-CD40L and IFN-gamma upregulates:

Answer 35

Expression of CD80/CD86 and stimulates Ag cross-presentation, which makes them more efficient at inducing differentiation of CD8+ cells.

Question 36

How do CD8+ cells cause CTL differentiation w/o helper T cells?

Answer 36

CD8+ T cells recognize Ag and costimulators on APCs which causes CTL differentiation w/o helper T cells. IL-12.

Question 37

How do CD4+ helper T cells stimulate CTL differentiation?

Answer 37

CD4+ helper T cells produce cytokines that stimulate CTL differentiation. IL-2.

Question 38

How do CD4+ helper T cells enhance APCs ability to stimulate CTL differentiation?

Answer 38

They increase IFN-gamma causing increase of IL-12 which produces a potentiated response.

Question 39

What is the immunologic synapse and what is its fuction?

Answer 39

It is the small space between CTL and target cell. It ensures that normal bystander cells are not injured by CTLs.

Question 40

Fas/FasL mediated cell killing

Answer 40

FasL on CTL interacts with Fas on target cell, which triggers apoptosis.

Question 41

Two major mechanisms of killing:

Answer 41

Fas-FasL mediated and granzyme-mediated apoptosis.

Question 42

Granzymes A,B,C are:

Answer 42

Serine proteases.

Question 43

Granzyme B is the only one show to be:

Answer 43

Required for CTL toxicity in vivo.

Question 44

Perforin is homologous to:

Answer 44

C9 complement protein.

Question 45

Fas/FasL mediated apoptosis mechanism:

Answer 45

Binding of Fas/FasL recruits procaspace-8 via FADD adaptor and converts it to caspace-8. In type I cells, caspace-8 directly cleaves caspace-3. In type II cells, caspace-8 cleaves Bid which causes release of cytochrome C. Cytochrome C combines iwth Apaf-1, activates caspace-9 which activates caspace-3. Caspace-3 activates CAD via degredation of ICAD. Activated CAD causes DN degredation.

Question 46

How does Mycobacteria evade the IS?

Answer 46

Inhibits phagolysosome fusion.

Question 47

How does HSV evade the IS?

Answer 47

Inhibits Ag presentation by interfering w/ TAP transporter.

Question 48

How does CMV evade the IS?

Answer 48

Inhibition of Ag presentation via removal of MHC I from the ER.

Question 49

How does EBV evade the IS?

Answer 49

Inhibition of Ag presentation by inhibiting proteosomal activity.

Question 50

How does Pox virus evade the IS?

Answer 50

Inhibition of effector cell activation.