T cell activation #1 Flashcards
What are the principal functions of the following: TCR
recognition
What are the principal functions of the following: CD3,4,8,28
signal transduction
What are the principal functions of the following: Integrin
adhesion
What are costimulatory signals? What is the purpose?
They are additional signals which allow activation- enhance T cell proliferation
If T cell has TCR it binds to … on APC
MHC
If T cell has CD28 it binds to … on APC
B7
If T cell has CD40L it binds to … on APC
CD40
If T cell has ICOS it binds to … on APC
ICOSL
If T cell has OX40 it binds to … on APC
OX40L
If T cell has CTLA-4 it binds to … on APC
B7
If T cell has PD-1 it binds to … on APC
PD-L
What does adhesion molecules pairs do?
allow T cell + APC to act
What are the adhesion pairs (there are 3!)
o ICAM-1 –> LFA-1
o LFA-3 –> CD2
o LFA-1 –> ICAM-3
What pairings turns on T signal + turns it off?
On: B7 (APC) –> CD28 (T cell)
Off: B7 –> CTLA-4
What is clonal activation?
- APC + MHC interact with T cell + TCR
- In T cell - ILR alpha is made –> this makes IL-2R
- IL-2R has 3 domains
- T cell proliferation happens + clonal expansion
- they T cells move into homing tissues
What CD makes cytokine?
cd4+
What are the receptors on epithelium T cell need to bind to to do their function?
- VLA-4 and CCR10
- CCR9 and α4β7
- CCR10 and cutaneous lymphocyte antigen (CLA)
Where is VLA-4 and CCR10 found?
tissues and site of inflammation
Where is CCR9 and α4β7 found?
mucosal nodes
Where is CCR10 and cutaneous lymphocyte antigen (CLA) found?
skin
What are killer T cells supposed to do?
graft rejection + kill tumor cell
What is the cells killed by CTL called?
target cell
T/F - T cells are released in periphery immature.
TRUE- they are released as pre-cytotoxic t cell
What is cross presentation?
A way to activate CD8+
APC cell with virus –> dendritic cell phagocytose –> Dendritic cell presents this virus to T cell –> > T cells that attack this virus is formed
How to activate CD4+ and CD8+ with dendritic cell (dc)?
DC –> bind to CD4/CD8 (depend on MHC) –> BOTH RELEASE IL2 (can happen separately or at the same time)
How to activate naiive CD8+ with dendritic cell (dc)?
DC –> MHC 2 –> makes more CD40 + IL-12 –> Then activates naïve CD8+
What is antigen specific killing?
attack antigen (release granzyme for spec antigen)
What is cell contact killing?
sticking with cell
What is sequential killing?
kill 1 target cell –> detach –> kills another –> detach etc
Does CD8+ kill by inflammation?
no- only apoptosis
What are the 2 ways CD8+ kills on it’s own?
- Granzymes –> are serine protease (Granulysin- a granzyme –kills intracellular bacteria: listeria + mycobacteria)
- FAS/FAS L –> Trimerization (2 domains from FAS + 1 from FAS L – they make 1 head) –> activates caspases –> apoptosis
What is TH0 cell subset?
- Earliest activated T cell or naïve T cells
* Differentiates into one of the T cell subsets
What does TH1 release?
IFN GAMMA + IL 2
What is the function of TH1?
- Innate: Activate macrophage + NK –> kill bacteria
- Virus: Cd8+ –> kill virus
- Hypersensitivity: Delayed hypersensitivity
- Remove bacteria: B cell makes IgG3 –> activate complement (remove bacteria)
- Autoimmune: MS (multiple sclerosis) + RA (rheumatoid arthritis)
What is the 2 function of TH2? and what do they need to release to do them?
IL4 + IL 13 –> B cell make IgE + IgG4
IL5 –>activate eosinophil
function together: they kill worm + parasites
What does Th17 release?
IL17 + IL 22
What cells does TH17 activate?
neutrophil + epithelial cell activation
What is the function of TH17?
kill fungi + extracellular bacteria + autoinflammation (MS + RA + psoriasis)
What is Treg? And what is needed to activate it?
activate: TGF beta
function: suppress T cell + APC + b cell
What is induced + natural Tregs?
- Induced T regs (iTregs) develop in the periphery
* Natural T regs (nTregs) develop in thymus and are auto-reactive
What is TFH? The TF needed? What does it secrete? What is it’s receptor?
helps B cell in secondary lymphoid organs
• TF: Bcl6
• Secrete: IL- 21
• Receptor: CXCR5
What is Th9 made by? what it secretes? What does it cause?
- Made by: IL4 + TGF beta
- Secrete: IL 9
- Causes: chronic inflammation (asthma + autoimmune)
What does Th22 secrete?
IL-22
What is a memory T cell?
it remembers an infection encountered before
Where is memory T cell found? Where does it circulate?
- Found in: skin + mucosa (most important)
* Central memory cells circulate in: peripheral lymph node
