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immuno > chapter 9 > Flashcards

chapter 9 Flashcards

1
Q

T cells develop in ___ and then enter the bloodstream
-once they reach a secondary lymhoid organ, they leave the blood stream and migrate through lymphoid tissue, returning via lymphatics to blood

A

Thymus

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2
Q

mature circulating T cells who have not encountered antigen are called ____

A

naive T cells

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3
Q

Once T cells encounter an antigen with MHC, they proliferate and differentiate into cells called____

A

effector T cells

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4
Q

Adaptive immune responses are intiated in the secondary lymphoid organs: _____

A

spleen, lymph nodes, MALTs (peyer’s patch in gut)

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5
Q

T and B cells are partitioned into distinct regions of secondary lymphoid tissues by the actions of ____

A

chemokines

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6
Q

what is the secondary lymphoid tissue?
-antigen free or as cargo in dendritic cell
-delivered to B cell/T cell zones
-B/T cells enter from high endothelial venules (HEV)

A

Lymph node

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7
Q

what is the secondary lymphoid tissue?
-antigen via arterioles which branch from central arteriole to marginal sinus
-in marginal zone antigen is taken by APC to T cell zones or B cell follicles

A

spleen

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8
Q

what is the secondary lymphoid tissue?
-antigen from lumen via microfold (M) cells to dendritic cells in subepithelial region

A

peyer’s patch

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9
Q

circulating B and T cells come to secondary organs by common route. Then they move into distinct regions under control of ____

A

chemokines

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10
Q

stromal cells and bone marrow derived cells in B-T cell zones produce cytokines. they produce ___.

A

CCL21

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11
Q

dendritic cells have a receptor for CCL21. Dendritic cells migrate. They then secrete ____. this then attracts T and B cells.

A

CCL19

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12
Q

-present in abundace at barrier tissue sites. In the absence of infection or tissue injury, they have low levels of costimulatory molecules so are not capable of activating naive T cells
-once they see antigen (in variety of ways), they pick it up, process it and present it
-mature conventional dendritic cells activate naive T cells

A

conventional dendritic cells

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13
Q

what type of dendritic cell has a role in adaptive immunity?

A

Conventional

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14
Q

-are sentinels for viral infections and secrete large amounts of class I interferons
-not as efficient in activating T cells
-play role in innate immune response. may help conventional cells sustain production of IL-12 which asks T cells to mak IFN-gamma

A

plasmacytoid dendritic cells

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15
Q

conventional dendritic cells are activated through stage to become activated APCs in peripheral lymphoid tissue
-entry to the tissue is based on chemokine receptor they express
-tissue resident DCs are phagocytic via receptors such as:______

A

dectin, DC-sign, Langerin

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16
Q

conventional dendritic cells are activated through stage to become activated APCs in peripheral lymphoid tissue
-at site of infection, TLR signaling causes them to get activated
-Induction of CCR7. cells expressing this are sensitive to ____ and ___ produced by lymphoid tissue

A

CCL19 and 21

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17
Q

conventional dendritic cells are activated through stage to become activated APCs in peripheral lymphoid tissue
-CCR7 forces migrated of dendritic cell to lymphoid tissue
-costimulatory molecule B7 made and MHC expressed
-by the time they arrive to the lymph node, they are activators of ___, present antigen, no more phagocytosis

A

naive T cells

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18
Q

what is the difference between conventional dendritic cell and plasmacytoid dendritic cell?

A

the difference is who can activate a T cell and who can not

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19
Q

Macrophages are ____ that can be induced by pathogens to present foreign antigens to naive T cells

A

scavenger cells

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20
Q

resting macrophages have few or no ___ and no ____

A

MHCII and B7

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21
Q

____are non migrator and do not go to T cell zones

A

tissue resident macrophages

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22
Q

macrophages in lymphoid organs (lymph node, marginal sinus) but do not activate T cells. Function is to ____.

A

ingest foreign agents

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23
Q

macrophages and B cells present antigen primarily to receive help from effector T cells in the form of ___ or ____

A

cytokines or surface molecules

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24
Q

where are dendritic cells found?

A

anywhere in the body

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25
Q

where are macrophages found?

A

lymphoid tissue, connective tissue and body cavities

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26
Q

where are B cells found?

A

lymphoid tissue and peripheral blood

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27
Q

B cells are highly efficient at presenting antigens that bind to their surface ____
- the internalized antigen is processed and bind to ____.

A

immunoglobulin; MHC II molecules

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28
Q

antigen presenting cells deliver 3 signals for the clonal expansion and differentiation of naive T cells, what are the 3 signals?

A

activation, survival and differentiation

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29
Q

what occurs at these 3 signals?
1. activation ____
2. survival ____
3. differentiation ____

A
  1. MHC-TCR
  2. co-stimulatory molecule, allows increased proliferation and survival of T cells (here CD28 and B7)
  3. Effector response by T cell depends on 3rd signal. Cytokines do this signal.
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30
Q

additional co-stimulatory pathways are involved in T cell activation
-B7 whose receptor is ___ and ___ on T cell

A

CTLA-4 and CD28

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31
Q

-_____is an inhibitory molecule of T cells
-____serves to regulate proliferative phase of T cell response

A

CTLA-4

32
Q

____ binds B7 more avidly than does ___ and delivers inhibitory signal to activated T cells

A

CTLA-4; CD28

33
Q

proliferating T cells differentiate into effector T cells that do not require co-stimulation to act
1. both signal received, activated, secretes and responds to IL-2. this increases expression of ___
2. IL-2 signaling enhances ____ and contributes to differentiation of T cell effector cells
3. now any encounter with antigen will trigger___

A
  1. IL-2 receptors
  2. clonal expansion
  3. action (no costimulation needed)
34
Q

CD8 T cells can be activated in different ways to become cytotoxic effector cells. Because of toxic effects of CD8 T cells, they need additional activation via ___; these molecules come from dendritic cells to activate CD8 T cells to produce IL-2

A

stimulatory molecules

35
Q

CD8 t cell activation needs help from ___

A

CD4 T cell

36
Q

CD4 T cell: APC interaction further activates CD4 to release IL-2 which activates CD 8 T cell
or dendritic cell forces T cell to activate ____ which when bound to CD40 on APC, Increases B7 production and 4-1BBBL production which activate CD8 T cell more

A

CD40L

37
Q

IFN-gamma acts on macrophages ingestion

A

TH1

38
Q

-goblet cells
-IL-5 recruits eosinophils
-IL-4 mast cell/basophil

A

TH2

39
Q

-IL-17 induces local epithelial cells to make chemokines to bring neutrophils
-also makes epithelial cells produce antimicrobial peptides
-extracellular bacteria

A

TH17

40
Q

-ready to activate a B cell
-follicular helper cells

A

TFH cells

41
Q

-kept in stage suppressing immune system don’t want CD4 or CD8
-lack of T cell activation
-suppress T cell and innate immune cell activity to prevent auto immunity

A

Treg cell

42
Q

APC/dendritic cells (innate immune cells) produce ____. The environment, exposure to pathogens etc, determine which cytokines the innate sensor cells will produce

A

cytokines

43
Q

Th1 cells differentiate in response to ____ and ___
-if no pathogen is present then, the TGF-beta and IL-2 will force the cells to differentiate into T regulatory cells

A

IFN and IL12

44
Q

each cytokine that specifies the development of specific effector cells activates different members of the ___ family of transcription factors

A

STAT

45
Q

1.T cell effector function involves interaction of T cell with a target cell displaying ____
2. focusing mechanism is common to all effector cells but action is dependent on ____

A
  1. antigen
  2. type of T cell engaged
46
Q

initial interaction between T cell and target cell is mediated by non specific cell adhesion molecules (like ICAMS). Allows T cell to stay in contact and then scans for ____

A

MHC: peptide complex

47
Q

what are the functions of TH1/

A
  1. activate macrophages
  2. secret IFN-gamma to activate infected cells
  3. FAS ligand activation triggers death of FAS bearing targets
48
Q

___ promote response to parasites and promote allergic responses. They help B cell activation (CD40L binds CD40 on B cells to proliferate them) and secrete B cell growth factors

A

TH2

49
Q

___ produce IL17 and IL22 acute inflammation by recruiting neutrophils to site of infection

A

Th17

50
Q

___ act at a distance and exert inhibitory actions via cell to cell interactions

A

Treg Cytokines

51
Q

to eliminate viruses, which are inside a cell, you need the work of ___

A

cytotoxic T cell

52
Q

cytotoxic T cell target the infected host cell for death. cells die in a variety of ways, what are they?

A

necrosis and apoptosis

53
Q

cell disintegration from tissue damage with antibody/complement is called __

A

necrosis

54
Q

is a regulated process induced by extracellular signals

A

apoptosis

55
Q

apoptosis can be __ or __

A

extrinsic or intrinsic

56
Q

activation of death receptors by extracellular ligands

A

extrinsic

57
Q

induced in response to noxious stimuli or lack of growth factors needed for survival

A

intrinsic or mitochondrial pathway

58
Q

apoptosis is mediated by ___ who are protected from acting by protector proteins

A

executioners

59
Q

the release of executioners causes the release of ___ from mitochondria and subsequent cell death

A

cytochrome C

60
Q

release of Cyt-C is controlled by Bcl-2 proteins. there are 2 groups:

A

promote apoptosis and inhibit apoptosis

61
Q

___ proteins are induced by stimuli that promote cell survival. These proteins bind to mitochondrial membrane and prevent the release of cyt C

A

anti-apoptotic

62
Q

___ family proapoptotic also are sentinel proteins. they (Bad, Bil, PUMA) once activated by stimuli either block anti apoptotic proteins or directly stimulate

A

Bcl-2

63
Q

what are the executioners

A

Bax, Bak, Bok

64
Q

what are the protectors?

A

Bcl-2, Bcl-XL, Bcl-W

65
Q

proteases that trigger apoptosis in target cell

A

granzymes

66
Q

___which helps deliver granzymes to target cells

A

perforin

67
Q

effector molecules produced are either cytotoxins or cytokines
-they have FAS ligand, which binds FAS on target cell and activates _____

A

apoptosis

68
Q

what are the cytotoxic effector molecules?

A

perforin, granzymes, granulysin, FAS Ligand

69
Q

perforin and granzymes needed for effective target cell killing granzymes trigger apoptosis by activating ___ and by damaging mitochondria which in turn activates caspases

A

caspases

70
Q

aids in delivering contents of granules into the cytoplasm of target cell

A

perforin

71
Q

serine proteases, which activate apoptosis once in the cytoplasm of the target cell

A

granzymes

72
Q

has antimicrobial actions and can induce apoptosis

A

granulysin

73
Q

cytotoxic t cells are selective ____ of targets expressing a specific antigen

A

serial killers

74
Q

T cells focus secretion on point of __ with target cells and move the granules to release right near the cell

A

contact

75
Q

cytotoxic T cells can also act by releasing cytokines not just inducing apoptosis:

A

IFN-Gamma; TNF-alpha and LT-alpha

76
Q

inhibitors viral replication directly and increases expression of MHC-I raises chance of cytotoxic attack, recruit macrophages to site

A

IFN-gamma

77
Q

recruit macrophages, kills cells by interacting and inducing apoptosis

A

TNF-alpha and LT-alpha

immuno (3 decks)

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