Immunological tolerance Flashcards
(35 cards)
Where does B cell central tolerance occur?
bone marrow
B cell central tolerance
receptor editing
apoptosis
B cell peripheral tolerance
apoptosis
anergy
clonal ignorance
Where does T cell central tolerance occur?
thymus
T cell central tolerance
positive selection
negative selection
What cells undergo positive selection?
thymic epithelial cells
What cells undergo negative selection?
macrophages
DCs
Positive selection cells that do not bind MHC molecules
apoptosis
Positive selection Bind class II molecules
mature to CD4 cells
positive selection bind class I molecules
mature to CD8 cells
negative selection strongly bind self-MHC or self antigen
apoptosis
negative selection some self reactive CD4 cells develop into…
t regs
T cell peripheral tolerance
apoptosis
Clonal ignorance/anergy
TCR affinity for antigen in T cell peripheral tolerance
self MHC complex too low for T cell to be removed
t/f all self antigens are expressed in the thymus
false
T/f self reactive T cells cannot infiltrate into immunologically privileged sites
true
antigen in t cell peripheral tolerance
expressed in too low amounts
affinity for TCR too low to trigger response
t cell peripheral tolerance and apcs
absence of co-stim molecules on apcs
what induce t cell anergy in t cell peripheral tolerance?
tregs
tolerogenic DCs
Loss of tolerance results in what?
autoimmunity
How can infection break tolerance?
- disrupt tissue barrier
- infect APCs
- bind pathogen to self proteins
- molecular mimicry
- superAg
specific immunological non-reactivity to an antigen resulting from a previous exposure to same antigen
immunological tolerance
need to induce tolerance
transplantation
need to break tolerance
cancer