Tolerance and autoimmunity

Question 1

define tolerance

Answer 1

an acquired inability to respond to antigenic stimulus

Question 2

what is central tolerance

Answer 2

removal of T and B cells which could be problematic

Question 3

what is peripheral tolerance

Answer 3

removal of problematic T and B cells after they’ve been released because some antigens are not expressed in the thymus or bone marrow

Question 4

what is the mechanism of peripheral stimulation

Answer 4

anergy: naive T cells require costimulation for full activation and without this they do not proliferate or produce factors 
active suppression (T reg cells)

Question 5

what is the mechanism of central tolerance

Answer 5

cells with high affinity TCRs are selected against and die by apoptosis
surviving cells are MHC restricted with low/intermediate affinity for self-peptide

Question 6

what is the mechanism of SLE development

Answer 6

antibodies are made against nuclear complexes and the immune complexes are then deposited around the body

Question 7

what is the mechanism of Grave’s disease (autoimmune thyroid diseases)

Answer 7

antibody binds to TSH receptors and stimulates the thyroid to produce thyroid hormones. negative feedback method does not work