front 1 A developing T cell first learns self-tolerance in which organ? | back 1 D. Thymus |
front 2 The thymic process that teaches developing T cells tolerance
to self is called what? | back 2 B. Central tolerance induction |
front 3 T-cell precursors enter the thymus after exiting which site? | back 3 A. Bone marrow |
front 4 A newly arrived thymocyte lacks CD4, CD8, and TCR. What best
describes it? | back 4 C. Receptor-negative immature |
front 5 After entering the thymus, immature T cells migrate outward to
proliferate in which region? | back 5 D. Cortex |
front 6 In the thymic cortex, immature T cells begin gene rearrangement to
form which receptor? | back 6 B. TCR |
front 7 After successful TCR rearrangement, immature thymocytes begin
expressing TCR plus which co-receptors? | back 7 A. CD4 and CD8 |
front 8 A thymocyte expressing both CD4 and CD8 is called what? | back 8 C. Double-positive |
front 9 A receptor-negative immature thymocyte is
protected from apoptosis by high
expression of what? | back 9 B. Bcl-2 |
front 10 Very immature thymocytes express little to no which apoptosis-related
molecule? | back 10 D. Fas antigen |
front 11 The thymic test for MHC restriction is called what? | back 11 A. Positive selection |
front 12 Positive selection is performed mainly by which thymic cells? | back 12 C. cTECs |
front 13 Positive selection asks whether a thymocyte’s TCR can recognize
what? | back 13 D. Self-MHC |
front 14 A thymocyte cannot recognize self-MHC during positive selection. What
is its fate? | back 14 B. Apoptosis |
front 15
cTECs generate some self-peptides for presentation by
digesting their own cytoplasm through what
process? | back 15 C. Autophagy |
front 16 cTECs can load autophagy-derived peptides onto which molecule? | back 16 A. Class II MHC |
front 17 cTECs may also present protein fragments taken from which
source? | back 17 D. Thymus environment |
front 18 During or shortly after positive selection, thymocytes usually become
what? | back 18 B. Single-positive |
front 19 After a thymocyte recognizes self-MHC, it begins expressing which
chemokine receptor? | back 19 A. CCR7 |
front 20 CCR7 expression directs selected thymocytes toward which thymic
region? | back 20 C. Medulla |
front 21 The medulla attracts CCR7-positive thymocytes because it contains
abundant what? | back 21 B. CCR7 ligands |
front 22 Negative selection occurs mainly in which thymic region? | back 22 D. Medulla |
front 23 Negative selection asks whether the thymocyte recognizes what? | back 23 A. Self-peptides |
front 24 A thymocyte strongly recognizes self-peptide on MHC. What
happens? | back 24 C. It is destroyed |
front 25 Failure of negative selection can predispose to what? | back 25 B. Autoimmune disease |
front 26 Which medullary cell helps test thymocytes for self-tolerance?
| back 26 D. mTEC |
front 27 mTECs help delete autoreactive T cells through which process? | back 27 C. Negative selection |
front 28 mTECs generate self-peptides partly through what cellular
process? | back 28 A. Autophagy |
front 29 mTECs express which transcription factor to display tissue-specific
antigens? | back 29 D. AIRE |
front 30 AIRE is best classified as what? | back 30 B. Transcription factor |
front 31 AIRE allows mTECs to express antigens normally found where? | back 31 C. Peripheral tissues |
front 32 mTECs use AIRE to express more than how many tissue-specific
proteins? | back 32 A. One thousand |
front 33 A child has defective AIRE. Which process is most directly
impaired? | back 33 B. Negative selection |
front 34 A thymocyte fails to bind self-MHC. Which selection
step eliminates it? | back 34 A. Positive selection |
front 35 A thymocyte binds self-peptide too strongly. Which
selection step eliminates it? | back 35 C. Negative selection |
front 36 Which thymic cell type is most associated with AIRE expression? | back 36 B. mTEC |
front 37 Which thymic cell type is most associated with testing MHC
restriction? | back 37 C. cTEC |
front 38 What is the purpose of central tolerance induction? | back 38 C. Prevent self-reactive T cells |
front 39 Why is AIRE important for central tolerance? | back 39 D. It displays peripheral antigens |
front 40 The thymocyte migration sequence is best summarized as which
pathway? | back 40 B. Cortex to medulla |
front 41 A second thymic cell type helps test developing T cells for
self-tolerance in the medulla. What is this cell called? | back 41 B. Thymic dendritic cell |
front 42 Thymic dendritic cells are abbreviated as what? | back 42 C. TDC |
front 43 Thymic dendritic cells contribute to tolerance testing by presenting
what? | back 43 B. Self-antigens |
front 44 TDCs present self-antigens on which molecules? | back 44 A. MHC molecules |
front 45 In addition to making self-antigens, TDCs also receive self-antigens
from which cells? | back 45 B. mTECs |
front 46 Medullary thymic dendritic cells are resident cells of which
region? | back 46 C. Thymic medulla |
front 47 Medullary TDCs develop from which precursor source? | back 47 A. Bone-marrow-derived precursors |
front 48 The final thymic output should recognize which structure? | back 48 C. Self MHC-peptide complex |
front 49 Mature thymic graduates should not recognize self-antigens presented
by which cells? | back 49 B. TDCs and mTECs |
front 50 A T cell exits the thymus after testing. Which receptor profile is
desired? | back 50 C. Recognizes self MHC-peptide |
front 51 A young thymus tests approximately how many double-positive cells
daily? | back 51 C. 60 million |
front 52 Of the daily double-positive thymocytes tested, approximately how
many single-positive cells exit? | back 52 B. 2 million |
front 53 Most double-positive thymocytes tested daily undergo what fate? | back 53 D. Apoptosis |
front 54 Roughly what percentage of tested thymocytes mature and exit
daily? | back 54 C. 3% |
front 55 The Goldilocks hypothesis addresses how one TCR can signal which
outcomes? | back 55 B. Selection, deletion, activation |
front 56 According to the Goldilocks hypothesis, why do so few thymocytes
mature? | back 56 A. Most cannot signal correctly |
front 57 A T cell survives thymic testing because its TCR interaction strength
is “just right.” What does this imply? | back 57 C. Balanced self-MHC recognition |
front 58 During positive selection, surviving T cells should have what type of
interaction with self MHC-peptide? | back 58 A. Relatively weak |
front 59 Why must self MHC-peptide interaction be relatively weak? | back 59 A. Allows focus on antigen |
front 60 In the Goldilocks model, interaction with self-peptide presented by
medullary TDCs should be what? | back 60 B. Very weak |
front 61 A thymocyte binds self-peptide on medullary TDCs too strongly. What
happens? | back 61 B. It is killed |
front 62 A thymocyte’s interaction with self-peptide is weak enough to avoid
deletion but sufficient for later APC interaction. What does this
represent? | back 62 A. Goldilocks signaling |
front 63 Even after thymic exit, many T cells die because they fail to find
what? | back 63 B. Cognate antigen |
front 64 If a naive T cell never finds cognate antigen, it dies after
approximately how long? | back 64 C. 6 weeks |
front 65 Some T cells pass negative selection despite being self-reactive
because their antigen is what? | back 65 B. Very rare |
front 66 Escaped self-reactive T cells often fail to cause disease because
their cognate antigen is unlikely to be found where? | back 66 B. Secondary lymphoid organs |
front 67 A T cell escapes deletion because its rare tissue-specific antigen
was not encountered. What is this cell? | back 67 A. Self-reactive T cell |
front 68 Rare tissue-specific cognate antigens may allow some T cells to pass
which process? | back 68 B. Negative selection |
front 69 In the thymic medulla, a subset of CD4 T cells
becomes which regulatory population?
| back 69 C. nTregs |
front 70
Natural regulatory T cells are selected mainly in
which location? | back 70 B. Thymic medulla |
front 71 nTregs arise from which broad T-cell type? | back 71 A. CD4 T cells |
front 72 T cells with weak affinity for self-antigens are generally selected
to become what? | back 72 A. Th cells |
front 73 T cells with too strong affinity for self-antigens are usually
what? | back 73 B. Destroyed |
front 74 T cells with intermediate affinity for self-antigens
are selected to become what? | back 74 C. nTregs |
front 75
nTreg-selected cells are induced to express which
gene? | back 75 D. Foxp3 |
front 76 Foxp3 expression is associated with which regulatory lineage? | back 76 A. Regulatory T cells |
front 77 nTregs become activated when they encounter which antigen type? | back 77 A. Self-antigen |
front 78 Once activated, nTregs suppress which cells? | back 78 B. Potentially self-reactive T cells |
front 79 The main protective role of nTregs is preventing damage from which
cells? | back 79 A. Self-reactive T cells |
front 80 Both nTregs and iTregs express
which protein? | back 80 C. Foxp3 |
front 81 Which regulatory T-cell type protects mainly against
self-reactive T cells?
| back 81 B. nTregs |
front 82 Which regulatory T-cell type restrains overreaction to
foreign invaders?
| back 82 D. iTregs |
front 83 nTregs and iTregs both express Foxp3 but differ mainly in what? | back 83 A. Target of suppression |
front 84 Which regulatory cell is naturally selected within the thymus?
| back 84 C. nTreg |
front 85 Which regulatory cell is inducible from naive Th
cells in peripheral settings?
| back 85 B. iTreg |
front 86 A potentially self-reactive virgin T cell leaves
normal circulation and enters kidney tissue. Which
safety mechanism protects against autoimmunity here? | back 86 B. Peripheral tolerance induction |
front 87 A virgin T cell recognizes cognate antigen on a nonprofessional
tissue cell but receives no second signal. What happens? | back 87 B. It undergoes class switching |
front 88 A virgin T cell recognizes antigen on a normal kidney cell but does
not activate. What signal is missing? | back 88 C. Co-stimulation |
front 89 Why does a normal kidney cell usually fail to activate a virgin T
cell? | back 89 A. It lacks B7 |
front 90 A virgin T cell becomes anergized after
recognizing antigen without co-stimulation. What is
its eventual fate? | back 90 C. Death |
front 91 A rare self-reactive virgin T cell receives such strong antigen
crosslinking that co-stimulation is bypassed. Which backup mechanism
limits it? | back 91 C. Activation-induced cell death |
front 92 Instead of testing every single T cell perfectly, the immune system
uses at least how many tolerance mechanisms? | back 92 D. Five |
front 93 Most B cells are tolerized in which location? | back 93 B. Bone marrow |
front 94 A developing B cell recognizes self-antigen in the bone marrow. What
process gives it another chance? | back 94 A. Receptor editing |
front 95 Receptor editing most directly involves rearrangement of which B-cell
component? | back 95 D. Light chain |
front 96 A germinal-center B cell undergoes somatic hypermutation and develops
self-reactivity. Why is activation by FDCs unlikely? | back 96 B. Self-antigens usually aren't opsonized |
front 97 A self-reactive B cell arises after somatic hypermutation. Why is
T-cell help unlikely? | back 97 A. Matching Th cells are absent |
front 98 A virus-infected cell downregulates Class I MHC to evade CTLs. Which
immune cell can kill it? | back 98 C. NK cell |
front 99 NK-cell killing of cells with reduced Class I MHC is called
what? | back 99 D. Missing-self recognition |
front 100 In missing-self recognition, NK cells kill because they fail to
receive what signal? | back 100 B. Inhibitory signal |
front 101 The inhibitory signal for NK cells depends on recognition of which
host molecule? | back 101 A. Class I MHC |
front 102 An NK cell cannot recognize the body’s Class I MHC. Without
licensing, what risk would this create? | back 102 A. Autoimmune NK killing |
front 103 NK cells must be licensed through which screening process? | back 103 C. Positive selection |
front 104 During NK-cell licensing, functional NK cells must bind what? | back 104 B. Self-MHC |
front 105 NK cells that cannot bind self-MHC during licensing become
what? | back 105 A. Anergized |
front 106 Which scenario best illustrates peripheral tolerance induction?
| back 106 C. T cell sees antigen, no B7 |
front 107 Which scenario best illustrates receptor editing? | back 107 A. Self-reactive B cell rearranges light chain |
front 108 Which scenario best illustrates missing-self recognition? | back 108 C. NK cell senses low MHC I |
front 109 A self-reactive B cell after somatic hypermutation usually fails
because it cannot efficiently get which two supports? | back 109 A. FDC antigen and Th help |
front 110 Which tolerance mechanism is specific to B cells in this
material? | back 110 B. Receptor editing |