Diebel- IL and T/B cell activation Review

Question 1

IL-2 is produced by?

Answer 1

Activated T cells

Question 2

What does IL-2 do?

Answer 2

Supports growth and expansion of most T cell populations, NK cells and B cells

Question 3

How are T cells activated?

Answer 3

T cells (CD4) become activated through APC

TCR/CDR: MHCIIpeptide
CD28:B7 (CD80/86)

Question 4

What happens if only TCR/CDR:MHCII peptide are activated w/ out CD28:B7?

Answer 4

Anergy= guards against autoimmunity

Question 5

What is CD25?

Answer 5

IL-2R

Any cell w/ this receptor can respond to IL-2

Question 6

IL-10 is made by….

Answer 6

Treg and Th2 cells

Question 7

What does IL-10 do?

Answer 7

Shuts off T cells that are already active and blocks the ability for more T cells to become active:

1. Blocks IL-2 (down regulating IL-3 and CD25)
2. Global down regulation of T cell cytokines
3. Down regulate MHCII expression

Question 8

IL-12 is produced by…

Answer 8

macrophages and DCs

Th1–> IFNy–> activates M1–> IL12

Question 9

What does IL-12 do?

Answer 9

Helps to support survival and growth of Th1 and blocks growth of Th2

Question 10

What makes IL-35 and what does it do?

Answer 10

T reg

Increases T reg expansion and leads to T reg proliferation and increased IL-10 production

Question 11

What produces TGF-B? What does it do?

Answer 11

Treg cell

Blocks IL-1 nad IL-2 dependent T cell proliferation.

Question 12

What two cytokines can convert Th1 to Treg?

Answer 12

TGF-B

Question 13

IFN-y is produced by_______and leads to _______.

Answer 13

Th4 T cells

M1 angry activators

Question 14

What are the two ways that B2 B cells are activate?

Answer 14

Bystander effect

Direct interaction

Question 15

Are B2 B cells thymus independent or dependent?

Answer 15

Dependent

Question 16

Describe the activation of B2B cells through the bystander effect.

Answer 16

1. BCR binds to TCR/CD4
2. CD40L (T cell) interacts w/ CD40 on APC
3. Licensing of APC
4. Cytokine release

Question 17

Describe the activation of B2B cells through the direct interactions.

Answer 17

1. B cells display antigens through MHCII
2. Recruit CD4 T directly
3. CD40 on B cell interacts w/ CD40L on T cell–>
4. Direct stimulation

Question 18

B1 B cells are dependent on what pathway?

Answer 18

TI-1

TI-2

Question 19

BCR, TLR and CD5 are surface markers on what cell?

Answer 19

B1 B

Question 20

Describe how B1 B cell activation occurs through the TI-1 pathway.

Answer 20

Activation through TLR/BCR–> polyclonal or monoclonal response at same time in the body

Question 21

What is a polyclonal response?

Answer 21

All B cells have TLR w/ TI-1 antigens can interact w/ regardless of what BCR recognizes–> different lineages of B cells responding at the same time–> polyclonal response

Question 22

Describe how B1 B activation occurs through the TI-2 pathway.

Answer 22

Activation through BCR–> linenage w/ same type of BCR reacting to SAME antigen–> monoclonal response

Question 23

What does CTLA-4 do?

Answer 23

Over time, the lower expression of CD28 and upregulated expression of CTLA-4–» more CTLA-4 than CD28 on cell surfaces–> effectively competes for binding to B7–> dampens signal to T cell

Question 24

What happens when APCs are activated by contact w/ antigen?

Answer 24

APC goes from making low MHC/B7 to high levels

Question 25

High levels of MHC/B7 leads to….

Answer 25

Robust immune response!

Interaction between CD40L:CD40–> IL-12–> survival and growth of Th1

Question 26

What is CCR7?

Answer 26

Upregulated on activated APCs

Moves APCs from tissue to secondary lymphoid organs

Question 27

What happens if you have a defect in CCR7?

Answer 27

You can’t traffic to LNs

Question 28

When is CD44 expressed and what does it do?

Answer 28

Expressed early on in T cell diff

Helps T cells to escape bone marrow and go to thymus

Question 29

What is tolerance?

Answer 29

Low levels of MHC/B7 and no co-stimulation –> anergy

Way to weed out T cells that shouldn’t respond to a particular antigen.