T cell Immunity Flashcards
Immature DC cells to active DC cells
Actived by danger signals and down regulate phago and micropin, gain ability to migrate and up regular CCR7
increase B7 and Cytokines
Purpose of lymphnodes
centers of testing for DC cells to test T cells so dont need all over body
what is Recirculation
Leave blood and stay in 2ndary for a day before migrating back
T cell extravasation
Roling - L selection binds w/ addresssin cam on HEV cells
Activation - CCR7 and ligand activate chemokines that make integrin for next step
Adhesion - LFA-1 bind HEV to ICAm
Diapedesis - Migrates to lymphnode
What is HEV
high end venules - vessels that flow into the lympnode and place where T cell extravasation occurs
How do T cells leave the lymph if not matched
Medullary sinus and efferent lymphatic
Clonal Expansion for T cells
Signal 1 (TCR binds to MHC- II) - CD3 (CD4 too short) Signals T cells and increases proteins for Anergy
Signal 2 (binds CD28(t) to B7(dc)) - Survial signal and stops Anergy unregulated CD40L
Signal 3 - DC cells direct differentiation into effector t Cells
IL- 2R and IL-2
produced by sig 1 and 2 and ensures T cell prolife
What is the importance in signal 2?
stop auto reactive T cells binding and preventing Perphieal tolerance
What is the importance of CTLA-4
Blocks over clones by CD28 b7 binding comp ( important for autoimmune drug disease
What signals get regulated when the T cell gets activated
Down S1P-R and increase CD69 ( decrease active t cells form leaving lymp)
Down L-selecting and CCR7 (signals that prevent effector T cells from leaving)
Increase VLA-4 and CXCL-8 ( allows e Tcells to leave)
Incrase CD44 and lFA-1 (helps to leave)
What is the importance of anti VLA-4
stops e t cells from over extravasation
Signal 3 TH17 targets
makes IL 6 & 17* (creates neutrophils)
for yeast and bacteria (EC)
Signal 3 TH1 targets
makes IL-2 and IFN- gamma
for virus and vesicular bacteria
IL- 6
TH17 and cause fevers
IL-17
TH17 recruits neutrophils
IL-2
Th1 activates CD8 cells
IFN- gamma
TH1 and activates macrophages and inhibits TH2 diff
Signal 3 TH2 targets
makes IL-4 & 5 and CD40L
for intestinal worms and allergies
IL -5
TH2 and recruits eosinophils for worms
Tfh
cytokines for B cells
Tregs
Cytokine released when PPR isnt inflame or activated
inhibits t cell prolife and prevent autoimmune disease
DC cells with TGF-beta and no PAMP or DAMP produce what?
Tregs bc TGF-Beta plus FOXP3 makes CD4 cells into TREGS
FOXP3 + _____ = ?
TGF - beta with no stree = CD4 into tregs
What happens to t cells after fight
some become Mem t cells and the rest get eaten up by phagocytosis
Central M T cells
express CCR7 in lymph + blood
float in blood and prolife fast
but need clonal expansion = slow working
Effector M T cells
Express CD45RO and constantly circulating
low prolife but immediate rxn
What DC signal triggers TH17
IL-6 and TGF - Beta from Yeast and EC bacteria
What DC signals trigger TH1
IL-12, IFN-Gamma from Virus and Vesicular bacteria
What DC signals trigger TH2
IL-4 from worms and allergies
What DC signals trigger TfH
IL-21 and binding to Binding to B cells
Resident M T cells
in tissue
poor prolife but fast rxn
