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68 Cards in this Set
- Front
- Back
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what receptors are present on the surface of mature T cells?
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T cell receptor
CD3 CD28 CD2 Either CD4 or CD8 |
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what cytokine is produced by CD4 TH17 cells?
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IL-17
(makes neutrophils better phagocytes) |
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what is the function of CD8 cytotoxic T cells?
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killing virus-infected cells
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what is the function of CD4 TH1 cells?
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activate infected macrophages
provide help to B cells for antibody production |
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what is the function of CD4 TH2 cells?
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provide help to B cells for antibody production
especially helps induce isotype switching to IgE |
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what is the function of CD4 TH17 cells?
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enhance neutrophil response
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what is the function of CD4 regulatory T cells?
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Suppress T cell responses
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what pathogens are targeted by Cytotoxic T cells?
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Viruses
some intracellular bacteria |
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what pathogens are targeted by TH1 cells?
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microbes that persist in macrophage vesicles
extracellular bacteria |
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what pathogens are targeted by TH2 cells?
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Helminth parasites
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what types of pathogens are targeted by TH17 cells?
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extracellular bacteria
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what class of MHC is recognized by cytotoxic T cells?
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MHC class I
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what proteins to kill virus-infected cells are contained in vesicles of cytotoxic T cells?
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perforin
granzymes |
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what is the function of perforin?
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similar to the C9 component of complement, perforin forms a pore in the target cell
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what is the function of granzymes?
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they are proteases which enter the pore produced by perforin and cleave important intracellular proteins and machinery
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what happens to cytotoxic T cells after killing a virus-infected cell?
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moves on to find another virus-infected cell
(not phagocytosed like neutrophils) |
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what is the effect, on lytic granules, of initial adhesion of a CTL to a target cell?
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nothing
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what is the initial adhesion of a CTL to a target cell?
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nonspecific adhesion
interaction of LFA-1 (T cell) with ICAM-1 (target cell) |
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what causes a CTL to become polarized? what does this mean?
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specific recognition of peptide:MHC complex by TCR
polarization of T cells is when MTOC, golgi apparatus and lytic granules align toward target cell |
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what is the major method used by CTLs to kill target cells?
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cytotoxin induced apoptosis
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what is the alternative (minor) mechanism used by CTLs to kill target cells?
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Fas-FasL mediated killing
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where is Fas Ligand (FasL) located?
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on cytotoxic T cell
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where is Fas located?
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on target cell
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what is the effect of Fas signalling?
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apoptosis in target cell
(cell to which Fas is attached) |
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what is an important function for Fas-FasL mediated killing?
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cleaning up overreactive T cells
(eliminating unwanted lymphocytes) |
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what class of MHC molecules are recognized by Helper T cells?
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MHC class II
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what types of immune responses can helper T cells activate?
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cell-mediated
humoral |
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what is the cell-mediated immune response to IFNgamma and CD40L?
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activate macrophages to destroy engulfed bacteria
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what is the cell-mediated immune response to FasL or LT?
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kills chronically infected macrophages, releasing bacteria to be destroyed by healthy macrophages
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what is the cell-mediated immune response to IL-2?
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Induces T-cell proliferation, increasing the number of effector T cells
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what is the cell-mediated immune response to IL-3 and GM-CSF?
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induces macrophage differentiation in the bone marrow
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what is the cell-mediated immune response to TNF-alpha and LT?
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activates endothelium to induce macrophage adhesion and exit from blood vessel at site of infection
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what is the cell-mediated immune response to CXCL2?
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causes macrophages to accumulate at site of infection (chemotactic molecule)
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what is LT?
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lymphotoxin
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what type of cells induce cell-mediated immune responses by secreting cytokines?
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TH1 cells
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what interaction between T helper cells and macrophages helps to activate the macrophages?
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CD40(on macrophages) with CD40L(on T helper cell)
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what two events result in macrophage activation by T helper cells?
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IFNgamma secretion by TH1 cells
CD40:CD40L interaction btwn. macrophage and TH1 cell |
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what gene expression is increased in macrophages as a result of activation by TH1 cells?
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B7 gene
MHC Class II |
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what mechanisms for killing intracellular pathogens are activated in macrophages via activation by TH1 cells?
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Fusion of phagolysosome
release of Oxygen radicals, NO, and proteases into phagolysosome |
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what causes granulomas to form?
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inability of macrophages to kill pathogens, causing immune system to recognize the pathogen as foreign and try to wall it off
(infected macrophages are rounded up and surrounded by T cells) |
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what is the cause of chronic granulomatous disease?
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inability of macrophages to produce reactive oxygen species (which kill bacteria)
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what interaction between TH2 cells and B lymphocytes activates the B cell?
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CD40(on B cell) with CD40L(on TH2 cell)
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what types of cytotoxins are secreted by CTLs?
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perforin
granzymes granulysin |
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what cytokines are released by CTLs?
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IFN-gamma
LT |
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what cytokines are secreted by TH1 cells?
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IFN-gamma
GM-CSF TNF-alpha LT IL-3 |
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what is GM-CSF?
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granulocyte macrophage colony stimulating factor
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what cytokines are secreted by TH2 cells?
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IL-4
IL-5 IL-10 IL-13 TGF-beta |
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what co-receptor is important in CTL-target cell interaction?
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Fas:FasL complex
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what co-receptor is important in TH1-macrophage interaction?
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CD40:CD40L complex
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what co-receptor is important in TH2-B cell interaction?
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CD40:CD40L complex
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what type of T cells express CD25 even as naive cells (unactivated)?
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Treg cells
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what percentage of peripheral T helper cells are Treg cells?
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5-10%
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what cytokines are secreted by Treg cells?
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IL-10
TGF-beta IL-4 |
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what is the main function of Treg cells?
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control autoimmunity
(peripheral tolerance) |
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what cytokine activates and produces Treg cells?
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TGF-beta
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what cytokines induce TH-17 cells?
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IL-6
TGF-beta |
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what cytokine is secreted by TH-17 cells? what is the function of this cytokine?
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IL-17
activation and recruitment of neutrophils |
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what is the drawback of IL-17?
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if overproduced, it could promote autoimmunity (autoimmune disorders)
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List the cytotoxic effector molecules of CTLs.
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perforin
granzymes granulysin FasL |
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List the cytokines secreted by CTLs that don't have cytotoxic effects.
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IFN-gamma
LT-alpha TNF-alpha |
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List the macrophage-activating effector molecules of TH1 cells.
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IFN-gamma
GM-CSF TNF-alpha CD40L FasL |
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List the cytokines secreted by TH1 cells which have no macrophage-activating effects.
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IL-3
LT-alpha CXCL2 (GRObeta) |
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List the B-cell activating effector molecules of TH2 cells.
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IL-4
IL-5 IL-13 CD40L |
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List the cytokines secreted by TH2 cells which have no B-cell activating effects.
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IL-3
GM-CSF IL-10 TGF-beta CCL11 (eotaxin) CCL17 (TARC) |
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List the cytokines secreted by TH17 cells that are involved in neutrophil recruitment.
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IL-17A
IL-17F IL-6 |
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List the cytokines secreted by TH-17 cells that have no neutrophil recruitment functions.
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TNF
CXCL1 (GROalpha) |
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Listh the suppressive cytokines released by Treg cells.
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IL-10
TGF-beta |
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List the cytokines released by Treg cells that have no suppressive functions.
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GM-CSF
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