13: Diff and Fxn of Cd8+ cells Flashcards

1
Q

percent of CD8+ in blood

A

33%

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2
Q

B cells make up what % of blood

A

30%

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3
Q

what are CD marker for

A

number of T cells by fluorescent microscopy and flow cytometry

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4
Q

where does rearrangement of genes for T cells occur

A

thymus

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5
Q

what is functional polarization

A

T cells take on a particular set of task that promote adaptive immune response as effector fxn

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6
Q

what can CD8+ become

A

CTL or memor cells

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7
Q

what are granules

A

lysosomes that have perforin and granzymes to kill other cells

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8
Q

secreted from CTLS

A

cytokines, mostly IFN-y that activate macrophages

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9
Q

what is the role of T bet in CTL

A

regulates TC of perforin

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10
Q

how does cross presentation work

A

DC ingest cell with intracellular microbes and produce both MHC II and MHCI due to phagosome in DC cytoplasm

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11
Q

what is it called when CD4+ enhance ability of APCs to stimulate CTLs

A

APC licensing

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12
Q

how does APC licensing work

A

CD4+ produces IFNy to DC then once CTL binds DC, IL12 is released to CTL

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13
Q

what is needed in APC licensing

A

CD40 to CD40L to up-regulate CD 80/86 expression for more efficient binding of CTLs

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14
Q

what signal do CD4+ provide for CTL

A

signal 3 via IL12 and IFNy

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15
Q

when are CD4+ required for CTL activation

A

weak innate immunity to latent viral infection and tumors

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16
Q

IL2 for CD8 means

A

proliferation and differentiation into CTL and memory

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17
Q

what does IL2 share

A

IL2R with IL15 and IL 21 at y

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18
Q

role of IL12 and IFNy to Naive CD8

A

effector CTLs

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19
Q

why are IL12 and IFN y required for effector CTLs

A

induce survival and development

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20
Q

what is role of IL15

A

produced by DC and tissue Macrophages for survival of memory CD8 T cells

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21
Q

IL21 role

A

produced by activated CD4+ T cells for induction of T cell memory and prevent CD8 + memory

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22
Q

how does IL2 work

A

autocrine loop for activation of T cells and up-reg of IL2, IL2R

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23
Q

CD4+ derived IL2 for activation of CD8+ via

A

paracrine

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24
Q

structure of IFNy from CD4+

A

homodime

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25
Q

what releases IFNy

A

TH1, CTLs, NK cells

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26
Q

role of IFNy

A

activator of macrophages to increase metabolic, phagocytic and killing

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27
Q

what does IFNy increase the expression of

A

MHC I and MHC II

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28
Q

what might be an important component for antiviral protection

A

IFNy making more MHC

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29
Q

key cytokine made by activated DC and macrophages

A

IL12

30
Q

profound effect of IL12

A

CD4 to TH1 effector cells

31
Q

what determines whether CD4 becomes TH1 or 2

A

balance of IL12 and 4

32
Q

which pro-inflammatory cytokines are promoted by IL12

A

IFNy and TNF B

33
Q

why are CD8+ stimulated by IL12 needed

A

effective in controlling tumors and maintain higher numbers

34
Q

what does IL12 prevent

A

CD8+ T cell exhaustion

35
Q

what other cells are activated by IL12

A

NK cells

36
Q

source of IL 15

A

macro and DCs

37
Q

what is IL15 similar to

A

IL2 for shared receptor

38
Q

what can IL 15 cause

A

proliferation of CTLS but favors TH1 cell in vitro

39
Q

what is a chemoattractant for T cells from blood

A

IL 15

40
Q

causes proliferation of memory CD4+ and CD8+ cells

A

IL 15

41
Q

IL21 is derived from

A

CD4+

42
Q

what does IL21 cause

A

DC, CD4+, NKT, NK, CTL, macrophage, macrophage activation. CD4 becomes TH17, B cell switching

43
Q

role of CD8 in acute viral infection

A

eliminate infection by becoming CTLs

44
Q

activated CD8+ cells produce what

A

chemokines and cytokines for eliminate infection

45
Q

role of CD4+ for CD8+ cells

A

stimulate DC and CD8 for CD8+ T memory cells

46
Q

which Ags are presented to CD8 T cells

A

viral Ags

47
Q

what happens after viral clearance

A

contraction for apoptosis

48
Q

same virus means

A

CD8+ memory cells that last for years

49
Q

what is exhaustion of CD8+ T cells

A

chronic viral infection leads to gradually extinguished CD 8+ T cells

50
Q

exhaustion leads to

A

active suppression of immune due to more PD1 and less IFNy

51
Q

what diseases are more PD1 on T cells related to

A

HIV and Hep C virus infection

52
Q

effective immuno-therapy for tumors

A

Anti-Pd-1 Abs

53
Q

PD1 blocks production of

A

CTLS

54
Q

why does an immunological synapse have to be formed

A

protect bystander cells

55
Q

release of perforin and granzymes by

A

granule exocytosis

56
Q

point of no return for CTL

A

capase 3

57
Q

How is apoptosis induced

A

FasL on activated CTLs binds Fas on surface of target cells

58
Q

what activates capase 3

A

perforin for apoptosis

59
Q

two types of killing by CTLS

A

perforin/granzyme and Fas/FasL

60
Q

what ion is involved in Granzyme mediated apoptosis

A

Ca2+

61
Q

what types of proteases are Granzyme A,B,C

A

serine

62
Q

which granzyme is required for CTL cytotoxicity

A

B

63
Q

what is perforin homologous to

A

C9 complement protein

64
Q

what does perforin cause

A

internalization of it and granzymes

65
Q

what does Granzyme B activate

A

capase 3 for apoptosis

66
Q

what doe FAS/FasL cause in type 1 cells

A

recruitment of procapase 8 by FADD for active capase 8 to cleave capase 3

67
Q

Fas-FasL in type II cells

A

capase 8 cleaves Bid for cyt c release from mitochondria. cyt c and Apaf1 and ATP activate Capase 9 to activate Caspase 3 that activates CAD for DNA degradation

68
Q

caspase 3=

A

degrades ICAD for CAD activation to degrade DNA

69
Q

how are intracellular microbes defended against

A

CD8 and 4 together. Macrophage ingest then CD4= IFNy and IL2 to kill bacteria ad produce MHC I for CD8+ to kill cell

70
Q

virus enters cell and infects directly leads to

A

viral proteins degraded for MHCI presentation so APCs Take up viral product then present with MHC I and II for CD4+ by CD40 and CD8 to CD 80/86 for activation of CD8+. release of perforin and granzyems as well as TNFa and IFNy produced