PRRs Flashcards

1
Q

PRRs

A

Pattern recognition receptors

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2
Q

5 families of PRRs

A
Toll like receptors (TLR: surface, endosomal)
CLRs 
NOD-like receptors (NLRs) family 
RIG-like receptors (RLRs) family)
Cytosolic DNA sensors (CDS) family
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3
Q

PRRs on cell surface can

A

bind pathogen associated molecular patterns from ECM pathogens

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4
Q

TLRs: location, PAMP/DAMP ligands

A

surface and endosomal membranes of DCs, phagocytes, B cells, endothelial cells

PAMP/DAMP: microbial Ags (LPS, peptidoglycans, viral nucleic acids)

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5
Q

NLRs: location, PAMP/DAMP ligands

A

Cytosol of phagocytes, epithelial cells

intracellular crystals (urate and silica); changes in concentrations of ATP and ions lysosomal damage

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6
Q

RLRs: location, PAMP/DAMP ligands

A

cytosol

viral RNA

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7
Q

CDSs: location, PAMP/DAMP ligands

A

cytosol of many cell types

bacterial and viral DNA

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8
Q

CLRs: location, PAMP/DAMP ligands

A

plasma membranes of phagoctyes

microbial carbohydrates with terminal mannose of fructose

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9
Q

TLRs general

A

evolutionarily conserved PRR

form homodimers/heterodimers, recognize PAMPs and DAMPs

TLRs 1,2,4,5,6 expressed on cell surface
TLRs 3,7,8,9 expressed in endosomes

recognized CpG

receptor is TIR, Toll/IL-1 receptor homology domain

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10
Q

Signaling pathways of TLRs 1,2,4,5,6

A

1,2,4,5,6 use adaptor protein MyD88

MyD88 activates transcription factor NF-kB and AP-1

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11
Q

TLR 3

A

uses adaptor TRIP to activate IRF3 or IRF7 transcription factors

only TLR that doesn’t use MyD88

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12
Q

TLR 4

A

can activated both pathways

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13
Q

TLRs 7, 9

A

in endosome, use MyD88 and activated both NFkB and IRF7

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14
Q

Function of TLRs 1,2,4,5,6

A

1, 2, 5, 6 + MyD88 —> activation of transcription factors NF-kB and AP1

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15
Q

Function of TLRs 3

A

uses adaptor protein TRIF and activates the IRF3 and IRF7 transcription factors

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16
Q

Function of TLRs 4

A

can activated both pathways

17
Q

Function of TLRs 7 and 9

A

in endosome, uses MyD88 to activate both NF-kB and IRF7

18
Q

Role of TLRs in Innate Immune Response

A

expressed especially on macrophages and dendritic cells

19
Q

IL-12

A

cytokine which controls the adaptive T-cell immune response

20
Q

Activation of TLRs trigger what kind of pathways

A

ones that directly kill the pathogen

21
Q

Health problems related to TLRs

A

can contribute to tissue injury by inducing apoptosis

can lead to life threatening symptoms of septic shock

22
Q

Major TLR Signaling Pathways (major themes)

A

all use MyD88 except TLR3

TLR4 and 2 also engage TIRAP

TLR3 signals through TRIF

23
Q

Match the signaling mediator with the TLR

TRIF
TIRAP
TRAM

A

TRIF = TLR3
TRAP = TLR4, TLR2
TRAM used with TRIF in TLR4-MyD88 pathway

24
Q

NF-kB and AP-1

A

nuclear factor kB and activation protein 1: stimulate expression of molecules like inflammatory cytokines (TNS and IL-1 importantly)

25
IRF3 and 7
stimulate expression of type I interferons IFN-alpha and IFN beta
26
Lipoproteins/Lipopolysaccharide/CpG DNA ---> TLR ---> _________ ----> _______ -----> _________ (4 outcomes)
NF-kB ---> DNA ---> a. if tissue damage, apotosis of cell or b. sepsis c. antimicrobial response d. influence adaptive immunity (cell mediated)
27
LPS activates cells through
TLR4
28
CpGs activate
TLR9
29
Microbial lipoprotein activates
TLR2
30
How do TLRs influence cell mediate immunity?
by signaling the transcription of IL-12