T cell activation

Question 1

describe the key events that occur after T cell activation
-proliferation
-differentiation

Answer 1

-more anitgen specific cells to control or clear the pathogen
-T cells alter their function to tailer their response to the pathogen

Question 2

how conventional and unconventional T cells recognise pathogen/ antigen

Answer 2

• presented by MHC 1 and 11
  -presented by non-classical MHC molecules

Question 3

where are conventional and non conventional T cells found

Answer 3

conventional= recirculate through lymphoid organs and blood
unconventional- found in pathogen exposed tissues and ready to respond to an infection

Question 4

where are MCH1 and MHC2 expressed

Answer 4

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)

Question 5

difference between endogenous and exogenous presntation pathways
-what classed by
-function
-what pathogen protein brocken up by
-where the peptides loaded onto and where

Answer 5

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

Question 6

what does the costmulation molecule CD28 on T cell attack with on antigen presenting cell

Answer 6

CD80 and CD86

Question 7

the different ways to stop T cell responding
1) ignorance
2) resting dendritic cells (anergic)
3) surpession by regulatory T cell (Tregs)

Answer 7

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

Question 8

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

Answer 8

-perforin to make holes in infected cell
-granzymes