chapter 9

Question 1

3 pathways when immature lymphocyte recognizes of self antigen in central tolerance (thymus and bone marrow)

Answer 1

apoptosis
change in receptors (b cells only)
development of regulatory t lymphocytes (CD4 t cells)

Question 2

3 pathways in peripheral tolerance when recognition of self antigen occurs

Answer 2

anergy
apoptosis
supression

Question 3

this mech of peripheral t lymphocyte tolerance, TCR does not send activating signals and the t cell engages an inhibitory receptor
(functional unresponsiveness)

Answer 3

anergy

Question 4

this response in peripheral tissue on recognition of self antigens and suppress (inhibits) the activation of lymphocytes that also reognizes these self antigens

Answer 4

suppression

Question 5

regulatory t-cells suppress immune responses by

Answer 5

1. cytokine signaling (inhibits activation of target cells)
2. CTLA-4 expression (removes B7 from APCs)
3. high amounts of IL-2 receptor (depletes IL-2 in local area)

Question 6

3 principle mechanisms of central B lymphocyte tolerance (which are activated by t cells)

Answer 6

1. non-self reactive b cell (receptor editing: expression of new IgV region)
2. deletion (apoptosis)
3. anergic b cell (reduced receptor expression, signaling)

Question 7

unresponsiveness of the immune system to self antigens

Answer 7

immunologic tolerance