Lecture 21

Question 1

Main action of Type 1 IFN (alpha/beta)

Answer 1

Inhibit or slow viral replication
Anti-viral cytokine

Question 2

Signal that permits killing by Natural killer cells

Answer 2

Absence of MHC Class 1

Question 3

What do CTLs secrete

Answer 3

Type II IFN–>IFN gamma

Question 4

Function of IFN gamma

Answer 4

1) Increase MHC class 1 expression (in neighbouring cells)
2) Activates macrophages and stimulates the production of chemokines (that then can recruit additional macrophages and CD8+ T cells to sites of infection)

Question 5

Difference between Type 1 and Type 2 IFN

Answer 5

Type 1 IFN–>potent antiviral effects, effects of PRR activation
Type 2 IFN–>role in immune response against intracellular pathogens

Question 6

What do TH1 T cells respond to

Answer 6

Infections by viruses and intracellular pathogens

Question 7

What do TH2 T cells respond to

Answer 7

Parasites (Helminths), other extracellular pathogens, and also allergy

Question 8

What do TH17 T cells respond to

Answer 8

Infections by extracellular bacteria and fungi, also in autoimmunity

Question 9

What are TFH responses involved in

Answer 9

Activating B cells in the lymph node

Question 10

TH1 associated cytokines

Answer 10

IFN gamma
CD40 ligand

Question 11

TH2 associated cytokines

Answer 11

IL-4, IL-5, IL-13
CD40 ligand

Question 12

TH17 associated cytokines

Answer 12

IL-17, IL-22
CD40 ligand

Question 13

Treg associated cytokines

Answer 13

IL-10
TGF-beta

Question 14

3 Types of cross-regulation

Answer 14

1) IL-4 secreted by TH2–>inhibits TH1 differentiation
2) IFN-gamma secreted by TH1–>inhibits TH2 differentiation
3) IL-4 secreted by TH2, OR IFN-gamma secreted by TH1–>inhibit TH17 differentiation

Question 15

Which master transcriptional regulator suppress TH2 pathway

Answer 15

T-Bet

Question 16

Which master transcriptional regulator suppresses TH1pathway

Answer 16

GATA3

Question 17

Cytokine used for BOTH TH17 and Treg differentiation pathways

Answer 17

TGF-beta

Question 18

Cytokine that induces TH17 pathway INSTEAD of Treg

Answer 18

IL-6 (Decision point, acts as a switch)

Question 19

Which polarizing cytokines impact differentiation of T cells Signal 3

Answer 19

IL-4, IL-6, IL-12, IL-23
IFN-gamma
TGF-beta

Question 20

Which effector cytokines are produced by differentiated T cells

Answer 20

IL-4, IL-5, IL-13, IL-17, IL-21, IL-22
IFN-gamma

Question 21

Which cells leave lymph node and migrate to site of infection

Answer 21

TH1, TH2, and TH17 cells

Question 22

Which cells stay in lymph node and activate B cells

Answer 22

TFH cells

Question 23

TH1 associated polarizing cytokines (Signal 3)

Answer 23

IFN-gamma and IL-12

Question 24

TH1 associated effector cytokine

Answer 24

IFN-gamma

Question 25

TH1 associated master transcriptional regulator

Answer 25

T-Bet (transcription factor)

Question 26

How does TH1 activate cellular immunity

Answer 26

1) Macrophage activation
2) Activation and differentiation of naive cytotoxic T lymphocytes precursors into effector CTL (through CD40L binding)

Question 27

What do TH1 cell respond to

Answer 27

Intracellular pathogens (intracellular bacteria)
- ex. M. tuberculosis and Salmonella
Intracellular parasites
- ex. Leishmania and Toxoplasma
Viruses

Question 28

Transcription factors associated to TH1 cells

Answer 28

T-Bet (master transcriptional regulator), STAT 1, and STAT 4

Question 29

TH1 functions

Answer 29

1) Secrete IFN-gamma at point of interaction
2) Targets macrophages (TH1 cell TCR recognizes pMHC-II on surface of macrophage)
3) To aid in killing of microbes that persist in macrophage vesicles