Adaptive Immunity - T cells (part 2)

Question 1

What are the 3 signals required between dendritic cells and T cells for T cell activation?

Answer 1

TCR with MHC+antigen, costimulation, cytokines

Question 2

What adhesion molecules (receptors) are present on dendritic cells?

Answer 2

ICAM-1, DCSIGN, CD58

Question 3

What adhesion molecules (ligands) are present on T cells?

Answer 3

LFA-1, ICAM-3, CD2

Question 4

How does binding between dendritic cells and T cells go from low affinity to high affinity?

Answer 4

T cells recognise MHC cells with an antigen, leads to conformational change in LFA-1 which leads to high affinity binding

Question 5

What molecules are present on the dendritic cell for costimulation?

Answer 5

CD80/86

Question 6

What molecules are present on the T cell for costimulation?

Answer 6

CD28

Question 7

How are different types of CD4 cells generated?

Answer 7

cytokines form dendritic cells induces differentiation

Question 8

What type of CD4 cells does IL-12 give?

Answer 8

Th1

Question 9

What type of CD4 cells does IL-4 give?

Answer 9

Th2

Question 10

What type of CD4 cells does IL-6/IL-21, IL-23, TGFbeta give?

Answer 10

Th17

Question 11

What type of CD4 cells does IL-6 give?

Answer 11

TFH

Question 12

What type of CD4 cells does TGFbeta give?

Answer 12

Treg

Question 13

How do CD4 cells provide different functions?

Answer 13

By giving off different cytokines

Question 14

What type of cytokines does Th1 release?

Answer 14

IL-2, interferon gamma, LT

Question 15

What type of cytokines does Th2 release?

Answer 15

IL-4, IL-5, IL-13

Question 16

What types of cytokines does Th17 release?

Answer 16

IL-17A, IL17F, IL-6, IL-21, IL-22

Question 17

What types of cytokines does TFH release?

Answer 17

IL-21

Question 18

What types of cytokines does Treg release?

Answer 18

TGFbeta, IL-10

Question 19

What is the transcription factor involved in Th1?

Answer 19

T-bet

Question 20

What is the transcription factor involved in Th2?

Answer 20

GATA-3

Question 21

What is the transcription factor involved in Th17?

Answer 21

RORgammaT

Question 22

What is the transcription factor involved in TFH?

Answer 22

Bcl-6

Question 23

What is the transcription factor involved in Treg?

Answer 23

FoxP3

Question 24

What is the function of Th1?

Answer 24

macrophage activation, isotype switching to IgG

Question 25

What is the function of Th2?

Answer 25

mast cell activation, eosinophil activation, isotype switching to IgE

Question 26

What is the function of Th17

Answer 26

neutrophil recruitment

Question 27

What is the function of TFH?

Answer 27

Help B cell proliferation and differentiation

Question 28

What is the function of Treg?

Answer 28

dampen down immune response once infection is clear

Question 29

What is the difference between T-depedent and T-independent B cell responses?

Answer 29

T-depedent responses have protein based antigens and involves isotype switching, higher affinity antibodies and memory. T -independent responses are non-protein based antigens and doesn’t give isotype switching (only IgM), low affinity antibodies and no memory

Question 30

How do CD4 T cells help B cells?

Answer 30

CD4 T cells express CD40L and B cells express CD40 - leads to isotype switching

Question 31

Where do CD4 T cells and B cells meet?

Answer 31

At germinal centres at follicle/paracortex junction

Question 32

How do B and T cells get to the germinal centres?

Answer 32

B cells down regulate CXCR5 and up regulate CCR7, T cells down regulate CCR7 and up regulate CXCR5 - and both follow chemotactic gradient

Question 33

What kinds of cells are present at germinal centres?

Answer 33

Activate B cells, T follicular helper cells and follicular dendritic cells

Question 34

What is the function of follicular dendritic cells?

Answer 34

Antigen depot that drives B cell activation and affinity maturation

Question 35

How do CD4 T cells help in the activation of CD8 T cells?

Answer 35

CD4 T cells interact with dendritic cells to allow the dendritic cells to activate CD8 T cells - this is a function of the CD40L

Question 36

What are the two ways which cytotoxic CD8 T cells kill infected cells?

Answer 36

Perforin punches holes in membrane to allow granzymes to enter and induce apoptosis or fas-ligand fas interactions lead to apoptosis

Question 37

How do T cells get to the site of infection?

Answer 37

Because of expression of receptors - endothelial cells at site of infection express CCL5 and CXCL10 and T cells express CCR5, CXCR3 and VLA-4