lecture 7 Flashcards
not all self antigens are expressed in the thymus so potentially self reactive to antigens elsewhere. what transcription factor combats this
AIRE
what does AIRE (autoimmune regulator protein) do
turns on lots of tissue specific genes in the thymus
T cells can escape negative selctive by further rearrangement of
TCRα locus (like BCR light chain)
lymphocytes that recognise self AG can also become unresponsive know as
anergic
what are privileged sites
sites that that B and T cells cant get to (e.g eye, testis and CNS)
what do T reg cells do
turn other t cells off
T reg cells come from some of the T cells with
high affinity receptors for self antigens
natural T regs come from the thymus
induced t regs are
turned into T regs later
deficiency of T regs leads to
severe autoimmune syndrome
B cells that secrete IL-10 are
B regulatory cells
T helper 1 cells release what cytokine and what does it do
TFN-γ and activates macrophages to engulf bacteria more efficiently
if you have a worm infection you will produce more
T helper 2 cells
what cytokines do T helper 2 cells secrete and what do they do
IL-4, IL-5 and IL-13
they recruit cells that are good at firing out things that are good at destroying extracellular organisms (e.g eosinophils, mast cells and plasma cell)
what do CD4 T helper 17 cells promote
responses against fungi
Th1 express ligand which binds to
CD40 on macrophage
CD4 Th1 kill chronically infected macrophages, released bacteria destroyed by
healthy macrophage
Th17 secrete which cytokine
IL-17
what cytokines do CD4 T regs release
TGF-beta and IL-10
IL-10 inhibits what
APCs inhibiting further t cell activation
what signal determines what type of t cell the naive cell will become
signal 3
what cytokine from APCs cause Th1 response
IF-12 and IFN-γ
what cytokine from APCs cause Th2 response
IL-4
what transcription factors are expressed in each t cell
Th2- GATA3
Th1- T-bet
Th17- RORγT
Tfh- Bcl6
Treg- FoxP3
what do the pattern recognition receptors do
they recognise what the pathogen is causing the DC to secrete the cytokine which causes the correct T cell response (e.g Th1) for that pathogen
what do the pattern recognition receptors do
they recognise what the pathogen is causing the DC to secrete the cytokine which causes the correct T cell response (e.g Th1) for that pathogen
what pathogens does Th1 respond to
intracellular pathogens - most viruses, some bacteria and fungi
what pathogens does Th2 respond to
extracellular parasites - e.g worms
if the naive T cell receives IL-12 cytokine from the APC what molecule moves to the nucleus and turns on T-bet transcription factor promoting Th1
STAT4
if the naive T cell receives IL-4 cytokine from the APC what molecule moves to the nucleus and turns on GATA-3 transcription factor promoting Th2
STAT6
Th1 cytokines inhibit
development of Th2 and Th17
Th2 cytokines inhibit
development of Th1 and Th17
Th17 cytokines inhibit
development of T reg
T reg cytokines inhibit
all other t cell types
