T Cell II (CD4)

Question 1

What is the main function of CD4 cells?

Answer 1

Activate phagocytes and B cells

Question 2

What happens to the levels of CD40L expression after CD4 activation and what does it bind?

Answer 2

Increases after activation and interacts with macrophages, B cells, and dendritic cells (remember still need cytokines)

Question 3

Which cytokines activate TH1 cells?

Answer 3

IFN-gamma from NK cells and IL-12 from DCs or macrophages

Question 4

Which txn factors are required for TH1 differentiation?

Answer 4

STAT1, STAT4, and Tbet

Question 5

Which cytokines activate TH2 cells?

Answer 5

IL-4 from mast cells

Question 6

Which txn factors are required for TH2 differentiation?

Answer 6

STAT6, GATA-3

Question 7

Which cytokines activate TH17 cells?

Answer 7

TGF-beta, IL-6, and IL-23 from macrophages and DCs

Question 8

Which txn factors are required for TH17 differentiation?

Answer 8

STAT3 and ROR-gammaI

Question 9

Which cytokines activate TH9 cells?

Answer 9

TGF-beta and IL-4

Question 10

Which cytokines activate TfH cells?

Answer 10

IL-6

Question 11

What is the overall function of TH1 cells?

Answer 11

Macrophage and B-cell activation to kill intracellular bacteria

Question 12

What is the function of TH9 cells?

Answer 12

allergic inflammation

Question 13

What is the function of TfH cells?

Answer 13

Antibody generation for B-cell dependent responses

Question 14

Which cytokines do TH1 cells release?

Answer 14

IFN-gamma

Question 15

What are the functions of IFN-gamma released by TH1 cells?

Answer 15

1. B cell complement binding and opsonization with IgG

2. Classical macrophage activation (most important effect)

Question 16

What do macrophages do after being stimulated by IFN-gamma released by TH1 cells?

Answer 16

Produce reactive oxygen species (NO)
Secrete TNF, IL-1, IL-2 for leukocyte recruitment
Increase MHC expression for increased T cell activation

Question 17

What is a consequence of TH1 over activation?

Answer 17

Autoimmunity

Question 18

What is the overall function of TH2 cells?

Answer 18

Phagocyte-independent eosinophil-mediated immunity against helminths

Question 19

What cytokines do TH2 cells release?

Answer 19

IL-4, IL-5, and IL-13

Question 20

What is the effect of IL-13,IL-14 release by TH2 cells in terms of macrophages?

Answer 20

Activation of the alternative macrophage pathway for tissue protection and repair

Question 21

What is the function of IL-4 released from TH2 cells in terms of B cells?

Answer 21

B cell activation and antibody production. Causes IgE release that causes mast cell degeneration

Question 22

What is the function of IL-5 released by TH2 cells?

Answer 22

Eosinophil activation**

Question 23

What is the importance of the two different TH1 and TH2 macrophage activation pathways?

Answer 23

Balance of TH1 activation of classical pathway and TH2 activation of alternative pathway determines ability to fight infection

Question 24

What is the function of TH17 cells?

Answer 24

Pro-inflammation for extracellular bacteria and fungi

Question 25

Which cytokines do TH17 cells release?

Answer 25

IL-17 and IL-22

Question 26

What is the function of IL-17 released by TH17 cells?

Answer 26

Stimulates acute inflammation and release of other cytokines (chemokines, TNF, IL-1, IL-6). TNF = neutrophil and macrophage recruitment

Question 27

What is the function of IL-22 released by TH17 cells?

Answer 27

Maintained epithelial barrier function.

Question 28

What do both IL-17 and IL-22 released from TH17 cells stimulate?

Answer 28

Antimicrobial production

Question 29

What is the clinical relevance of TH17 activity?

Answer 29

May take part in chronic inflammation because has widespread effects on the body

Question 30

What microbes do CD4's mainly fight?

Answer 30

bacteria and parasites NOT viruses (extracellular)