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Week 2 Phys > 32 T cells > Flashcards

32 T cells Flashcards

1
Q

This form of T cell activation generates a diverse repertoire of mature T cells

A

Antigen independent activation

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2
Q

This form of T cell activation results in:

1) Activation (two signals: MHC complex + B7 binding or IL-2R activation)
2) Survival
3) Proliferation (clonal selection)
4) Differentiation into effector T cell or Memory T cell (always ready to switch to an effector T cell)

A

Antigen dependent activation

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3
Q

This type of T cell activation leads to apoptosis or anergy

A

TCR-MHC2 binding only

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4
Q

This type of T cell activation leads to proliferation, differentiation, and effector function

A

MHC2-TCR and CD28-B7 (CD80/86)

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5
Q

This type of T cell activation leads to cell-cycle arrest

A

MHC-TCR and (CTLA-4)-B7(CD80/86)

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6
Q

: IL-2 release from the CD4+ cell is a(n) ___ signal that binds to the IL-2 receptor and signals proliferation and activation.

A

Autocrine signal. Note: This is why experienced T cells have a lower threshold for activation (they already have many IL-2 receptors in the membrane)

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7
Q

binds to B7 by displacing CD28, blocking IL-2 synthesis. As a result, the antigen presenting cell becomes less effective at presenting antigens to T cells, and T cell activation is inhibited (anergy is the major outcome of this)

A

Cytotoxic lymphocyte antigen-4 (CTLA-4)

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8
Q

 Naïve T cells circulate through the lymph nodes and find antigens
 Activation of naïve T cells in the lymph nodes leads to development of effector cells, and clonal expansion
 These experienced T cells now have no business in the lymph nodes, and migrate to the site of infection (or other lymph nodes to meet B cells)
 Antigen presentation to experienced T cells: At the site of infection, macrophages and B cells present the antigen to experienced T cells, telling the T cells that their presence is indeed necessary there to help eliminate the infection. If the innate immune system has cleared the infection, no such signal will be received and the T cell will die

A

Activation and migration of T cells

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9
Q

T cells that have not divided into a specific subtype

A

Naive helper T cells (Th0)

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10
Q

subtype of T cell that is responsible for helping B cells produce antibodies (as well as assisting w/ class switching). Located in the follicles (w/ the B cells)

A

Follicular helper T cells

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11
Q

Subtype of T cell that activates macrophages to deal w/ intracellular infections

A

Effector helper T cells (Th1)

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12
Q

Subtype of T cell that activates neutrophils and induces inflammation

A

Effector helper T cells (Th17)

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13
Q

Subtype of T cell that induces production of IgE to deal w/ parasitic infections

A

Effector helper T cells (Th2)

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14
Q

Cytokines that cause Th0 cells to differentiate into Tfh cells

A

IL-6 and IL-21

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15
Q

This cell gives the 2nd signal to the B cell to differentiate and produce antibodies (remember that the 1st signal is antigen phagocytosis)

A

Follicular helper T cells

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16
Q

This cell type mainly deals w/ intracellular infections. I.e. microorganisms that evade the immune response and establish infections (ex: bacteria that prevent fusion of the phagosome w/ the lysosome)

A

Th1 cells

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17
Q

T/F
• A macrophage gets infected w/ a bacteria, and is unable to clear the bacteria from its cytosol.
• A dendritic cell now migrates to the lymph nodes and presents the antigen of this intracellular pathogen to a Th0 cell, which differentiates into a Th1 cell.
• The Th1 cell now secretes IFN-gamma (main secretion of these cells), which enhances the ability of macrophages to destroy the intracellular pathogen

A

True

18
Q

This cell type secretes IFN-gamma and helps the B cell to produce a particular type of IgE molecule (which is good at fixing complement, neutralizing the antigen, and activating macrophages). Only effective against extracellular pathogens

A

Th1 cell (secondary function)

19
Q

IL-2, TNF-alpha, and IFN-gamma are the major secretions of which cell type?

A

Th1 cells

20
Q

Th0 cells differentiate into Th1 cells in response to which cytokine? What cell type releases this cytokine?

A

IL-12. Released by activated macrophages

21
Q

This cell type makes macrophages better at killing microbes and better at presenting antigens (in case it cannot clear the infection, it can recruit help from CD8+ cells)

A

Th1 cells

22
Q

Signaling from which cytokine released from which cell type(s) results in differentiation into Th2 cells?

A

IL-4. Released by APCs

23
Q

The major function of this cell type is stimulating production of IgE

A

Th2 cells

24
Q

T/F. IL-4 secretion from Th2 cells induces B cells to produce IgM, which binds to a parasite and induces degranulation of mast cells –killing the parasite

A

False. . IL-4 secretion from Th2 cells induces B cells to produce IgE, which binds to a parasite and induces degranulation of mast cells –killing the parasite

25
Q

IL-4, IL-13, and IL5 are cytokines secreted by which cell type and what is their function?

A

They are secretions of the Th2 cell type. Their function is to attract cells that can bind IgE (granulocytes and mast cells) and increase intestinal motility. These are anti-parasite defenses

26
Q

The major cytokine of this cell type is IL-4. Promotes differentiation of Th0 into Th2 cells. Promotes switch to IgE (and IgG) production to deal w/ parasites. Responsible for allergic reactions. Inhibits Th1 production from Th0

A

Th2 cell type

27
Q

T/F. Th2 cells mediate the response against intracellular infections

A

False. Th2 cells mediate the response against parasites

28
Q

Which cell type secretes IL-17 and IL-22?

A

Th17 cells

29
Q

This cytokineattracts neutrophils to the site of inflammation by inducing the cells of the infected tissue to secrete the inflammatory cytokines (promoting inflammation). Also increases the production of anti-microbial peptides from epithelial cells

A

IL-17

30
Q

This cytokine activates cytotoxic T lymphocytes, inducing cell death by apoptosis

A

IL-2

31
Q

T/F. A dendritic cell must migrate from the site of infection to the lymph node to present the antigen to the T cell.

1) In this case, the first thing that the dendritic cell must do is present the antigen to a naïve T helper cell.
2) The T helper cell then activates the CD8+ cell
3) Two signals for activation: 1st signal from antigen, 2nd signal from T helper cell. Both are necessary for activation (which stimulates survival, proliferation, and differentiation)
4) The CD8+ cell then differentiates into memory T cells and Cytotoxic T lymphocytes (CTLs)

A

True

32
Q

T/F. Naïve CD8+ cells emerge from the thymus. Activation requires recognition of the cognate antigen-MHC by TCR and proper co-stimulatory signals (directly by APC or Th cell)

A

True

33
Q

o Perforin/granzyme-mediated cell killing: Perforin pokes hole in the membrane. Granzyme is then injected into the cell. Granzyme activates caspases, activating apoptosis
o Fas/Fas ligand mediated cell killing: The FasL on CTL surface interacts w/ the Fas receptor on the target cell, initiating the intrinsic pathway of apoptosis.

A

Mechanisms of cell death induced by cytotoxic T cells

34
Q

Defects in this cell type result in increased susceptibility to viral and intracellular bacterial infections and reactivation of latent virus infections (such as infection by the epstein-barr virus), which are normally kept in check by these cells

A

Cytotoxic T lymphocytes

35
Q

___ reactions are mediated by Th1 cells

A

Delayed type hypersensitivity reactions

36
Q

The classic inflammatory cytokines that function to recruit phagocytic cells to the site of infection

A

TNF-alpha & IL-1

37
Q

Certain B cells release this Ig isotype. The function is neutralization of the effect of the pathogen

A

IgG4

38
Q

Review diagrams

A

Do it

39
Q

Cytokines secreted by macrophages

A

TNF, IL-1, and IL-12

40
Q

This cell type enhances the killing capability of macrophages by increasing the rate of production of ROSs (ex: NO) and lysosomal enzymes

A

Th1 cells

41
Q

This cell type causes the macrophage to increase secretion of cytokines (TNF, IL-1, and IL12) and chemokines

A

Th1 cells

42
Q

This cell type causes the macrophage to increase expression of B7 and MHC in their membranes

A

Th1 cells

Week 2 Phys (17 decks)

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