T cell activation Flashcards
(16 cards)
describe the key events that occur after T cell activation
-proliferation
-differentiation
-more anitgen specific cells to control or clear the pathogen
-T cells alter their function to tailer their response to the pathogen
how conventional and unconventional T cells recognise pathogen/ antigen
- presented by MHC 1 and 11
-presented by non-classical MHC molecules
where are conventional and non conventional T cells found
conventional= recirculate through lymphoid organs and blood
unconventional- found in pathogen exposed tissues and ready to respond to an infection
where are MCH1 and MHC2 expressed
-are they endogenous or exogenous pathway
-what pathogens do they respond to
MHC1- expressed by all nucleated cells. and respond to intracelullar pathogens (virus) (endogenous pathway).
MHC11- expressed by antigen presenting cells : macrophages, DC, B cells (exogenous pathway). respond to extracellular pathogens (bacteria)
difference between endogenous and exogenous presntation pathways
-what classed by
-function
-what pathogen protein brocken up by
-where the peptides loaded onto and where
endogenous- MHC1
-cells infected by intracellular pathogen
-pathogen proteins brockne up be proteasome
-peptides loaded onto MHC1 in ER
exogenous- MHC11.
antigen presenting cells (macrophage, Dc, b cells)
cells infected by extracellular pathogen
-cells takes up pathogen by phagocytosis
-pathogen proteins brocken in endosome
-peptides loaded onto MHC11 in endosome
what does the costmulation molecule CD28 on T cell attack with on antigen presenting cell
CD80 and CD86
the different ways to stop T cell responding
1) ignorance
2) resting dendritic cells (anergic)
3) surpession by regulatory T cell (Tregs)
1) T cells never encounter antigen
2) present antigen without co stimulatory signals (CD80/ CD86) leading to T cell non-functional (anergy)
3) prevent T cell activation preventing autoimmunity
when activated CD8 T cell differentiate into killer/ cytotoxic T cells
-what molecules do they release and why
-what granules fuse with infected cell to casue apoptosis
-perforin to make holes in infected cell
-granzymes
During an infection activated effector T cell migrate to?
Site of infection
Which transcription factor is important for regulatory T cell development?
FOXP3
Which cell surface receptors enables neutrophils and macrophages to recognise bacterial compounds?
TLR-4
T cell receptors affinity is generated by?
Somatic hypermutation
NFAT (important T cell development) is activated by changes in intracellular levels of which secondary messenger
Calcium
What is extravastation
How immune cells move into inflamed tissues in the blood
How antibodies protect the host
Neutralising or opsonising pathogens
Are cytokines specific to antigens
No
