PCB 3233 IMMUNOLOGY EXAM 4
Positive0Selection0-0ans✔makes0sure0that0your0T-Cell0recognizes0one0of0your0MHC.
If0it0does0not,0then0apoptosis
Negative0Selection0-
0ans✔Makes0sure0it0does0not0recognize0your0peptide:MHC0too0strongly
Does0gamma:0delta0T-cells0have0to0go0through0positive0selection?0-0ans✔No
What0does0turning0off0RAG01&20do0to0your0gene0rearrangement?0-
0ans✔Preserve0the0current0rearrangement
Primary0Lymphoid0Tissue0-0ans✔bone0marrow0and0thymus
What0does0TH10cells0do?0-0ans✔Activate0macrophages
Thymal0Stromal0Cells0-0ans✔Keeps0BCR0genes0closed0and0opens0TCR0genes
IgM0activates?0-0ans✔complement
Notch-10-0ans✔The0signal0for0survival.0It0drives0the0cell0on0the0T-cell0path0—
0signals0to0open0up0T-cell0rearrangement.
Signaling0rearrangement0keeps0T-cel0on0T-cell0pathway
Where0does0Maturation0and0Positive0Selection0occur?0-0ans✔Cortex0of0the0thymus
Can0negative0selection0also0take0place0in0the0Cortex?0-
0ans✔Yes,0negative0selection0can0take0place0in0the0cortex0at0the0same0time0as0positiv
e0selection
Where0does0negative0selection0take0place?0-0ans✔medulla0of0thymus
Where0are0mature0thymocytes0located?0-0ans✔Medulla
Where0are0immature0thymocytes0located?0-0ans✔Cortex
, What0special0cells0are0in0the0Medulla0-
0ans✔Dendritic0cells,0macrophages,0and0medullary0epithelial0cells
What0special0cells0are0in0the0cortex?0-0ans✔Cortical0epithelial0cells0and0macrophages
Where0can0you0find0AIRE?0-0ans✔in0the0medullary0epithelial0cells
AIRE0-0ans✔Autoimmune0regulator
made0by0medullary0epithelial0cells
Creates0a0couple0hundred0peripheral0peptides0that0can0be0used0to0test0T-
cells0for0negative0selection
DiGeorge's0syndrome0-
0ans✔deletion0in0chromosome0220in0which0thymus0fails0to0develop0and0T-
cells0are0absent
Hassall's0corpuscles0-
0ans✔macrophages0in0both0cortex0and0medulla0remove0the0many0thymocytes0that0fail
0to0mature0properly
Involution0of0the0Thymus0-
0ans✔Progressively0shrinks,0fat0gradually0claiming0areas0once0packed0with0thymocyte
s
-reduces0production0of0new0T-cells
Double0negative0-0ans✔No0CD40and0CD8
Double0Positive0-0ans✔CD40and0CD80are0present
Single0Positive0-0ans✔has0either0CD40or0CD8
CD20and0CD50-
0ans✔perform0adhesion0and0signaling.0They0are0present0during0double0negative0stage
Thymocytes0rearrange0which030genes0at0the0same0time?0-
0ans✔Beta,0gamma,0and0delta
pTalpha0-
0ans✔surrogate0alpha0chain.0signals0cell0to0halt0gamma,0delta,0Beta0chains,0gene0rear
rangement0and0begin0proliferation.
What0do0macrophages0do0in0the0thymus?0-0ans✔continually0remove0dead0cells
Positive0Selection0-0ans✔makes0sure0that0your0T-Cell0recognizes0one0of0your0MHC.
If0it0does0not,0then0apoptosis
Negative0Selection0-
0ans✔Makes0sure0it0does0not0recognize0your0peptide:MHC0too0strongly
Does0gamma:0delta0T-cells0have0to0go0through0positive0selection?0-0ans✔No
What0does0turning0off0RAG01&20do0to0your0gene0rearrangement?0-
0ans✔Preserve0the0current0rearrangement
Primary0Lymphoid0Tissue0-0ans✔bone0marrow0and0thymus
What0does0TH10cells0do?0-0ans✔Activate0macrophages
Thymal0Stromal0Cells0-0ans✔Keeps0BCR0genes0closed0and0opens0TCR0genes
IgM0activates?0-0ans✔complement
Notch-10-0ans✔The0signal0for0survival.0It0drives0the0cell0on0the0T-cell0path0—
0signals0to0open0up0T-cell0rearrangement.
Signaling0rearrangement0keeps0T-cel0on0T-cell0pathway
Where0does0Maturation0and0Positive0Selection0occur?0-0ans✔Cortex0of0the0thymus
Can0negative0selection0also0take0place0in0the0Cortex?0-
0ans✔Yes,0negative0selection0can0take0place0in0the0cortex0at0the0same0time0as0positiv
e0selection
Where0does0negative0selection0take0place?0-0ans✔medulla0of0thymus
Where0are0mature0thymocytes0located?0-0ans✔Medulla
Where0are0immature0thymocytes0located?0-0ans✔Cortex
, What0special0cells0are0in0the0Medulla0-
0ans✔Dendritic0cells,0macrophages,0and0medullary0epithelial0cells
What0special0cells0are0in0the0cortex?0-0ans✔Cortical0epithelial0cells0and0macrophages
Where0can0you0find0AIRE?0-0ans✔in0the0medullary0epithelial0cells
AIRE0-0ans✔Autoimmune0regulator
made0by0medullary0epithelial0cells
Creates0a0couple0hundred0peripheral0peptides0that0can0be0used0to0test0T-
cells0for0negative0selection
DiGeorge's0syndrome0-
0ans✔deletion0in0chromosome0220in0which0thymus0fails0to0develop0and0T-
cells0are0absent
Hassall's0corpuscles0-
0ans✔macrophages0in0both0cortex0and0medulla0remove0the0many0thymocytes0that0fail
0to0mature0properly
Involution0of0the0Thymus0-
0ans✔Progressively0shrinks,0fat0gradually0claiming0areas0once0packed0with0thymocyte
s
-reduces0production0of0new0T-cells
Double0negative0-0ans✔No0CD40and0CD8
Double0Positive0-0ans✔CD40and0CD80are0present
Single0Positive0-0ans✔has0either0CD40or0CD8
CD20and0CD50-
0ans✔perform0adhesion0and0signaling.0They0are0present0during0double0negative0stage
Thymocytes0rearrange0which030genes0at0the0same0time?0-
0ans✔Beta,0gamma,0and0delta
pTalpha0-
0ans✔surrogate0alpha0chain.0signals0cell0to0halt0gamma,0delta,0Beta0chains,0gene0rear
rangement0and0begin0proliferation.
What0do0macrophages0do0in0the0thymus?0-0ans✔continually0remove0dead0cells
