Diebel- IL and T/B cell activation Review Flashcards
IL-2 is produced by?
Activated T cells
What does IL-2 do?
Supports growth and expansion of most T cell populations, NK cells and B cells
How are T cells activated?
T cells (CD4) become activated through APC
TCR/CDR: MHCIIpeptide
CD28:B7 (CD80/86)
What happens if only TCR/CDR:MHCII peptide are activated w/ out CD28:B7?
Anergy= guards against autoimmunity
What is CD25?
IL-2R
Any cell w/ this receptor can respond to IL-2
IL-10 is made by….
Treg and Th2 cells
What does IL-10 do?
Shuts off T cells that are already active and blocks the ability for more T cells to become active:
- Blocks IL-2 (down regulating IL-3 and CD25)
- Global down regulation of T cell cytokines
- Down regulate MHCII expression
IL-12 is produced by…
macrophages and DCs
Th1–> IFNy–> activates M1–> IL12
What does IL-12 do?
Helps to support survival and growth of Th1 and blocks growth of Th2
What makes IL-35 and what does it do?
T reg
Increases T reg expansion and leads to T reg proliferation and increased IL-10 production
What produces TGF-B? What does it do?
Treg cell
Blocks IL-1 nad IL-2 dependent T cell proliferation.
What two cytokines can convert Th1 to Treg?
TGF-B
IFN-y is produced by_______and leads to _______.
Th4 T cells
M1 angry activators
What are the two ways that B2 B cells are activate?
Bystander effect
Direct interaction
Are B2 B cells thymus independent or dependent?
Dependent
Describe the activation of B2B cells through the bystander effect.
- BCR binds to TCR/CD4
- CD40L (T cell) interacts w/ CD40 on APC
- Licensing of APC
- Cytokine release
Describe the activation of B2B cells through the direct interactions.
- B cells display antigens through MHCII
- Recruit CD4 T directly
- CD40 on B cell interacts w/ CD40L on T cell–>
- Direct stimulation
B1 B cells are dependent on what pathway?
TI-1
TI-2
BCR, TLR and CD5 are surface markers on what cell?
B1 B
Describe how B1 B cell activation occurs through the TI-1 pathway.
Activation through TLR/BCR–> polyclonal or monoclonal response at same time in the body
What is a polyclonal response?
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
Describe how B1 B activation occurs through the TI-2 pathway.
Activation through BCR–> linenage w/ same type of BCR reacting to SAME antigen–> monoclonal response
What does CTLA-4 do?
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
What happens when APCs are activated by contact w/ antigen?
APC goes from making low MHC/B7 to high levels
High levels of MHC/B7 leads to….
Robust immune response!
Interaction between CD40L:CD40–> IL-12–> survival and growth of Th1
What is CCR7?
Upregulated on activated APCs
Moves APCs from tissue to secondary lymphoid organs
What happens if you have a defect in CCR7?
You can’t traffic to LNs
When is CD44 expressed and what does it do?
Expressed early on in T cell diff
Helps T cells to escape bone marrow and go to thymus
What is tolerance?
Low levels of MHC/B7 and no co-stimulation –> anergy
Way to weed out T cells that shouldn’t respond to a particular antigen.
