T Cells III Flashcards
stimuli that activate T cells
MHC/peptide + co-stim, mitogens, agonist antibodies, chemical mediators, superantigens
MHC/peptide + co-stimulatory signal
TCR + CD28, TCR+CD40L
mitogens
PHA, conA (non-specific activation for proliferation)
agonist antibodies
anti CD3 + anti CD28, anti TCR + anti CD28
chemical mediators
PMA + calcium ionophores
T cell activation (proliferation)
requires 2 competence signals and 1 progression signal (3 total)
competence signals
TCR engagement and then a co-stimulatory signal
progression signal
IL-1, IL-4, IL-6, IL-12, TGF-beta
3 signals cause _
activation –> survival –> differentiation
activation
MHC-TCR binding
survival
B7-CD28 binding (B7=CD80)
differentiation
IL-6, IL-12, IL-4, TGF-beta (cytokines)
CD28 vs CTLA-4
CD28 is on naive T cells and CTLA-4 is after activation
CTLA-4
down-regulation; higher affinity for CD80
CD28
proliferation and differentiation
cytokine for Th1
IL-12
Th1 releases
IFN-gamma
cytokine for Th2
IL-4
Th2 releases
IL-4, IL-5, IL-13
cytokine for Th17
IL-6, IL-1b, TGF-beta
Th17 releases
IL-17, IL-21
cytokine for Treg
TGF-beta
Treg releases
TGF-beta and IL-10
cytokine for Tfh
IL-6, IL-21
Tfh releases
IL-21
Th1
classic immune response; releases IFN-gamma to stimulate macrophages
Th2
releases IL-4, IL-5, IL-13 to activate eosinophils and mast cells and cause IgE switch in response to parasites
Th17
releases IL-17 and mainly activates neutrophils
Tfh
provides help for B cells
Treg
regulates cells by inhibiting activation
TH1 effects of macrophage activation
increase MHC-II, increase TNF receptors, increase radicals, increase nitric oxide
B cell help by _
Th1, Th2, and mostly Tfh
Treg cells are characterized by _
CD4, CD25 expression
What is needed to stimulate CD8+?
4-IBBL
proteins in lytic granules of CD8+
perforin and granzymes
perforin
polymerizes to form a pore in target membrane
granzymes
serine proteases, which activate apoptosis once in cytoplasm of target cell
