Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
115 Cards in this Set
- Front
- Back
Which route(s) does the thymus receive T progenitor cells:
A. lymph B. blood C. both |
B
|
|
Which route(s) do the nature T cells leave:
A. lymph B. blood C. both |
B
|
|
Embryologic origin for the following cells in the thymus:
1. cortical epithelial cells 2. medullary epithelial cells 3. thymocytes 4. dendritic cells 5. macrophages |
1. ectoderm
2. endoderm 3. bone marrow 4. bone marrow 5. bone marrow |
|
What is the thymic analge composed of?
|
1. cortical epithelial cells
2. medullary epithelial cells |
|
What happens in Hassall's corpuscle?
|
site of thymic cell death
|
|
What Ig is expressed by double negative thymocytes?
|
CD2
|
|
Where is IL7 produced and what's its function?
|
IL-7 is made by the stromal cells of the red bone marrow and the thymus.
IL-7 is a hematopoietic growth factor capable of stimulating the proliferation of lymphoid progenitors |
|
What is the difference in DNA rearrangement between T cell and B cell development?
|
T cell does multiple TCR rearrangements simultaneously whereas B cell does it sequentially.
|
|
What are the two races in T cell DNA rearrangement?
|
1. β and γ:δ compete
2. α and γ:δ compete |
|
What is α:β pre T cell receptor made of?
|
β chain
surrogate α chain CD3 ζ |
|
What is the function of pre T cell receptor?
|
1. Triggers T cell proliferation
2. Halt β chain rearrangment. 3. Cells become permissive for TCR α chain locus rearrangement. 4. stimulates CD4 and CD8 co-receptors Ensures a T cell express only one type of TCR β chain. |
|
TCR β chain is similiar to which chain in B cell?
What is the difference in the gene make up between these 2 chains? |
Heavy chain.
TCR β chain can undergo second rearrangements because there are two sets of DJ and C gene segments that are tandemly associated with V gene segments. |
|
Which event triggers thymocytes to becone double positive?
|
Successful rearrangment of TCR β chain.
|
|
Where are double positive thymocytes loacted in the thymus?
|
inner cortex of the thymus
|
|
Which type of T cells emerge first during embryonic development?
A. α:β T cells B. γ:δ T cells |
B
|
|
Where do the three waves of γ:δ T cells migrate to?
|
1. epidermis
2. reproductive tract 3. diverse locations |
|
What are the dentritic epidermal T cells(dETC)?
|
First wave of γ:δ T cells that migrate to the skin.
|
|
Why do early γ:δ T cells express less diverse TCRs?
|
No TdT expression
limited selection of V region. |
|
Which genes are shut down during Pre T cell proliferation?
|
RAG1,2
|
|
T/F: Signal joints can not be replicated and an excised coding joint can be found in γ:δ T cells and B cells.
|
F.
|
|
Which event stops α chain rearrangement in T cells?
|
When T cell is positively seleced.
|
|
Where does positive selection take place in T cell development?
What cells are involved in this process? |
Cortex of the thymus
cortical epithelial cells: express both MHC1 and MHCII. |
|
What causes bare lymphocyte syndrome?
|
lack of expression of MHCI or MHCII by lymophocytes and thymic epithelial cells.
|
|
Negative selection in T cells is mediated by what cells?
|
dendritic cells.
|
|
Naive T cells are mature in _____ area.
|
T-cell rich area
|
|
What cells does HIV infect?
|
CD4 T cells
|
|
What is a mixed lymphocyte reaction?
|
Peripheral blood cells from one person are mixed in tissue culture with lethally irradiated cells from a second person of a disparate HLA type.
The magnitude of the alloreative response to nonself MHC provides an estimate of relative numbers of T cells that are negatively within the thymus of an individual. |
|
What percentage of the positively selected T cells is deleted in the thymus?
|
1%
|
|
Why is it not a good idea to increase the number of MHC molecules?
|
Increase the load of nrgative relection, T cell repretiore decreases.
|
|
Thymoma is a tumor of ____ cells.
|
thymic stromal cells or epithelial cells.
|
|
CD1 is expressed in what type of cells?
|
cortical thymocytes
intestinal epithelium |
|
CD1 is recognized by ____ cells.
|
NKT cells
|
|
Where do T cells encounter antigens?
|
secondary lymphoid tissues
|
|
T/F: Dendritic cells only triggers T cell response.
|
T.
|
|
Where do the pathogens enter our body through the following route end up:
1. through wound in skin 2. from gut 3. after entry into blood stream |
1. dendritic cells containing ingested pathogen carried to the nearest lymph node.
2. GALT (peyer's patches) though M cells. 3. Spleen. |
|
What is the cell surface glyprotein that distinguishes professional APC and is involved in co-stimulation?
|
B7
|
|
Which receptor does B7 bind to and what is the signal it produces?
|
CD28 on a T cell.
Activates the T cell and signals it to proliferate. |
|
Absence of B7-CD28 binding would lead to ____.
|
anergy
|
|
What mechanism other than negative selection are selfreactive T cells eliminated?
|
anergy: when self antigen is recognized, the lack of B7-CD28 interaction makes the cells inactive.
|
|
What are the differences between immature dendritic cells and mature dendritic cells?
|
immature: capture, uptake, and processing of antigens.
mature: develop fingerlike dendrites to interact with T cells. |
|
Immunological synapse is made between ____ and ____ cells.
|
T cell and APC
|
|
Immunological synapse is complosed of two regions: cental molecular activation complex(c-SMAC), and peripheral supramolecular complex(p-SMAC). What interations are specific in each region?
|
c-SMAC: TCR:antigen:MHC:CD4/CD8, CD2:LFA3, CD28:B7
p-SMAC: LFA1:ICAM1, LFA1:ICAM2, ICAM3:DC-SIGN |
|
What is homing process?
|
Movement of naive T cells into secondary lymphoid tissue.
|
|
What molecules are involved in the homing process?
|
T cell:endothelial cells
1. L-selectin:CD34 (addressin) 2. L-selectin:GlyCAM-1 (addressin) 3. LFA1:ICAM1 4. LFA1:ICAM2 5. CCR7:CCL21 (chemokines) |
|
LFA1 on T cell membrane is activated by ____.
|
CCL21
|
|
What adhesion molecules are involved in T cell and dendritic cell interaiton?
|
T cell:dendritic cell
1. LFA1:ICAM1 2. LFA1:ICAM2 3. ICAM3:DC-SIGN 4. CD2:LFA3 |
|
Which type of T cell leave the secondary lymphoid tissue?
|
CD8 T cells
|
|
What are the factors that contribute to the delay between initiation of infection and engagement of adaptive immune response? (3)
|
1. antigen activation of T cells
2. availability of antigen-specific T cells 3. prolifration and differentiation of antigen-specific large clone of effector T cells |
|
What molecule is found on mucosal epithelium that functions like GlyCAM and CD34 on HEV?
|
MadCAM-1
|
|
Which other molecule also binds to B7, but dampens down T cell activation and proliferation?
|
CTLA4
|
|
What are the three APC in the secondary lymphoid tissue?
Where is each one located? |
1. dendritic cell: T-cell area
2. macrophage:throughout 3. B cell: B cell area |
|
T/F: Macrophages are involved in both innate and adaptive immunity.
|
T
|
|
When Langerhan's cells mature, they become ____.
|
Interdigitaiting reticular cells.
|
|
As APCs, marophage has what types of receptors?
|
1. MHCs
2. mannose receptor 3. scavenger receptor 4. complement receptor 5. Toll like receptor |
|
As APCs, a B cell has what types of receptors?
|
1. MHCs
2. Toll like receptors |
|
Naive T cells are able to squeeze through endothelium and enter the cortex of lymphoid tissue as a result of interation between:
A. CD2 and LFA3 B. CD4 and MHC molecule C. LFA1 with ICAM1 and/or ICAM2 D. L-selectin and MadCAM-1 E. scavenger receptor and endothelium |
C.
|
|
What type of agen does each of the three APC present?
|
1. DC: all types, especially virus
2. macrophages: bacteria 3. B cells: peptides and protein antigens |
|
Which cell type never funcion as a professional antigen presenting cell?
A. B cell B. dendritic cell C. macrophages D. mast cell |
D.
|
|
An early result of the interaction between an antigen-presenting cell and a T cell is:
A. activation of complement B. activation of macrophages C. activation and proliferation of T cells D. apoptosis of the APC E. production of antibodies |
C.
|
|
Which special adhesion molecule does activated dendritic cell expressed and bind tightly to ICAM3 on T cell?
|
DC-SIGN
|
|
Which specific chemokine is made by activated dendritic cell that attracts T cells toward them?
|
CCL18
|
|
Langerhans cells:
A. accumulate in and remain in lymphoid tissue. B. express high levels of B7 molecules. C. express more MHC molecules than interdigitating cells. D. express a macrophage like morphology. E. phagocytose efficiently. |
E.
|
|
Why is adjuvants required for an effective vaccine?
|
It induces co-stimulatory activity in dendritic cells, macrophages, and B cells.
|
|
What's role of lipid rafts in cell signalling?
|
organize signal transduction proteins in proper complexes.
|
|
List three examples of lipid rafts.
|
1. sphingolipid
2. cholecterol 3. GPI anchor |
|
The initial signal to activate a T cell is conducted by:
A. CD3 B. ITAM C. ZAP70 D. Lck |
A.
|
|
Once ITAMS get the signal from CD3, they are phosphorylated by ___.
A. Lck B. Fyn C. CD45 D. NFAT |
B.
|
|
What is the role of Lck?
|
It associates with CD4/CD8 and activate ZAP70.
|
|
What is the role of CD45?
|
It helps activate Lck , Fyn, and other kinases.
|
|
What's the role of ZAP70?
|
Binds to ITAM of ζchain and activate PLC-γ and GEF(guanine-exchange factors).
|
|
What is the role of PLC-γ?
|
It cleaves PIP2 into IP3 and DAG.
|
|
What is the role of IP3?
|
increase intracellular Ca level and activate calcineurin.
|
|
What is the role of calcineurin?
|
Activates NFAT.
|
|
The combined action of what three molecules turn on the transcription of genes that direct T cell proliferation and differentiation?
|
NFAT
NFkB AP-1 |
|
Signal transduction initiated by antigen-induced activation of either B or T cell receptors is mediated by:
A. chemokines B. cytokines C. ICAMs D. ITAMs E. VCAMs |
D.
|
|
What is the role of DAG?
|
Activate NFkB.
|
|
AP-1 can be activated by____.
|
GEF(guanine exchange factor) through G protein linked MAPK cascade.
|
|
NFkB can be activated by ___.
|
DAG which activate PKC.
|
|
Which cytokine is responsible for proliferation and differentiation of activated T cells?
|
IL-2
|
|
Which of the following signal is needed to produce IL-2 by the activated T cell?
A. TCR:antigen:MHC signal B. costimulatory signal C. coreceptor signal D. all the above |
D.
|
|
What is the principle effect of the co-stimulatory signal?
|
To increase the synthesis of IL-2 by the T cell by 100 fold.
|
|
What does cyclosporin do?
|
Inhibit IL-2 production by disrupting signals from TCR.
|
|
What does rapamysin do?
|
Inhibit signaling from IL-2 receptor.
|
|
Cytokines made by Th1 cells lead to____.
|
1. macrophage activation
2. inflammation 3. production of opsonsizing antibodies that enhances phagocytosis. |
|
Cytokines made by Th2 cells lead to____.
|
1. B cell differentiation
2. production of neutalizing antibodies. |
|
How does autoreactive T cell aquire anergy?
|
lack of costimulaiton of CD28-B7.
|
|
What are the effector molecules of Th1 cells?
|
IFN-γ
GM-CSF TNF-α,β CD40 ligand IL3 Fas ligand |
|
What are the effector molecules of Th2 cells?
|
IL3,4,5,10,15
TGF-β CD40 ligand GM-CSF |
|
What effector molecules of cytotoxic T cells?
|
perforin
granzymes granulysin Fas ligand IFN-γ TNF-α,β |
|
Th1 cells recognized antigens bound to which class MHCs?
|
MHCII
|
|
Cytotoxic cells recognized antigens bound to which class MHCs?
|
MHCI
|
|
APCs that activate helper T cells express:
A. CD8 B. MHCI C. MHCII D. IgE |
C.
|
|
Helper T cells
A. are involved in production of IgA but not other isotypes. B. can differentiate into cytotoxic T cells C. interact with macrophages and B cells D. make it possible for macrophages to phagocytose antigen E. mediate immune responses to large polysaccharide antigens. |
C.
|
|
What are the three ways to activate a naive CD8 T cell?
|
1. activated dendritic cell
2. naive CD4 cell activate APC to make B7. 3. effector CD4 cell secrete IL-2 |
|
Which of the following events determines whether cytotoxic T cells rather than antibodies are produced during an immune response?
A. activation of T helper cells by APC. B. activation of macrophages to produce a stronger oxidative burst C. binding of CD4 to macrophage surface protein D. presentation of antigen on MHCI molecule E. whether antigen is degraded by macrophages. |
D.
|
|
What is a major difference between activated naive T cell and a effector T cell in stimulaiton?
|
no co-stimulation is needed for effector T cells.
|
|
Cytoplasmic tails of cytokine receptors are often associated with____.
|
JAK: Janus kinases
|
|
What is the signaling pathway of gene transription induced by cytokine binding with its receptor?
|
upon binding:
cytokine receptos domerize JAK phosphorylates STAT STAT dimerize, move to the neucleus to initiate gene transcription. |
|
Myelopoieses can be stimulated by which two cytokines?
|
GM-CSP and IL3
|
|
T/F: A coomon pattern is for a membrane associated cytokine and a secreted cytokine to work synergistically within a local area to fight infection.
|
T.
|
|
What is the main effect to IFNγ secreted by cytotoxic T cells?
|
inhibit viral replication
|
|
What are the 2 different ways of inducing apoptosis in infected cells by cytotoxic T cells?
|
1. perforin, granzymes, granulysin
2. Fas ligand |
|
Cytotoxic T cells:
A. are elicited pro=imarily by protozoan infections. B. kill by antibody-dependent cytotoxicity. C. kill virus-infected host cells. D. stimulate B cells to make antibody. E. stimulate neutrophils to attack bacteria. |
C.
|
|
Macrophages require 2 signals for activation:______.
|
1. IFN-γ
2. CD40L(T cell):CD40(macrophage) |
|
What cytokines inhibit macrophage activation?
|
TGF-β
IL-4 IL-10 IL-13 |
|
How does Th1 cells coordinate host responses to intravesicular pathogens?
|
1. IFN-γ, CD40L activates macrophages
2. Fas ligand or TNF-β to induces apoptosis of macrophages 3. bacteria released 4. bacteria killed by new macrophages |
|
What is the function of TNFα,β?
|
induces vascular endothelial cells to change adhesion molecules.
|
|
Granuloma contains ___ in the center area.
|
large macrophages(epitheloid cells): fusion of multiple infected macrophages
|
|
Granuloma contains ___ in the peripheral area.
|
activated T cells
|
|
What types of infection can lead to granuloma?
|
chronic infections resistant to macrophage killing mechanisms.
|
|
What is the benefit of granuloma?
|
shield infected area from vasular supply, cause the core to die.
|
|
What is caseation necrosis?
|
core of the glonuloma die because of lack of blood supply.
|
|
What is cognate interaction?
|
B cell and T helper cells recognize the same antigen but bind to different epitopes.
|
|
Which of the following cytokine stimulate B cell proliferation:
A. IL4 B. IL5 C. IL6 D. IL10 |
A.
|
|
What does regulatory(suppressor) T cell do?
|
release IL-4, 10, and TGF-β, CD25.
Regulate Th1 pathway. |