Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Infection Term 4 > Infection 2.1 > Flashcards

Infection 2.1 Flashcards

1
Q

What are the 3 stages of innate immune system?

A

RECOGNITION of microbes and damaged cells ACTIVATION of mechanisms ELIMINATIOn of unwanted substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens in the recognition stage?

A

uses pattern recognition receptors (PRR’s) to recognise PAMPs and responds rapidly to invading pathogens -activates other parts of the immune system and tissues throughout the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are PAMPs?

A

Pathogen associated molecular patterns molecular structures of microbial pathogen that required for survival

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What two molecules does the innate immune system recognise?

A

PAMPs DAMPs by PRRs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are DAMPs?

A

Damage associated molecular patterns result of cell damage by infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the types of PRR’s?

A

1) Extracellularly
2) Intracellularly
3) Secreted used to tag; activate complement cascade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are TLR’s?

A

Toll Like Receptors: expressed on plasma membrane and endosome membrane.

  • activation of these receptors initiates a cascade of events that activates
  • 3 main transcription factors:

1) NF-kB
2) AP-1
3) IRF’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the NF-kB?

A

make pro-inflammatory cytokines eg TNFalpha that enhances immune response, induces apoptosis of infected cell Pro IL-B and Pro-Il18 Interleukin will enhance immune response through its chemotaxis effect and activation of lymphocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the AP-1?

A

adaptor protein which causes the differentiation, proliferation and apoptosis of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are IRF’s?

A

interferon regulatory factors (IRF’s) that stimulate production of type I interferon (antiviral cytokines)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the transmembrane toll-like receptors?

A

identify bacterial structures or the outside of bacterial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the signalling cascade?

A

Initial: 1) Loop structure; leucine-rich repeats , will identify a PAMP on a passing bacteria/microorganism and sets up a cascade of events

2) Toll-IL-1 receptor (TLR) signalling domain gets activated, either Initial effect: or Alternate reaction
- recruitment of associated adaptor proteins to that particular area; causes nF-kB to be activated; transcription factor
- increases activation of NF-kB

-causes activation of a number of genes: ie cytokines adhesion molecules costimulators

  • Cytokines; attract neutrophils (recruitment), phagocytosis, signalling pattern, recruiting other immune cells+ acute inflammation
  • increased vascularisation and stimulation of adaptive immune system:
  • neutrophils recruit adaptive immune system to that site:

1) if friendly PAMP is detected, signalling cascade will not be activated

2)pathogen is detected, activation of:

-NFkB -increased cytokines

-acute inflammation+ secondary response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the alternate reaction?

A
  • activation of IRF’s
  • produces a type I interferon
  • produces cellular changes that produce an anti-viral state
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are NOD-like receptors and how do they react with the inflammasome?

A
  • highly conserved
  • cytosolic receptors that sense DAMPs and PAMPs in the cytoplasm+ recognise cell walls in pathogens
  • all NLR’s contain a NOD but different N-terminal domains (Nucleotide Oligomerisation Domain)
    1) NOD1 2)NOD2 3)NLRP3
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Difference between NOD1 and NOD2 AND NLRP3?

A
  • NOD1 and NOD2 have caspase-related domains in their N terminal and bind to peptidoglycan which activated NFkB
  • NLRP3 has a PYRIN N-terminal domain and recognises microbial products, substances that signal cell and damage/death (ATP, uric acid, potassium)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens when NLRP3 gets activated?

A
  • NLRP3 oligomerises with an adaptor protein and an inactive form of caspase 1 to form an INFLAMMASOME
  • once formed, the caspase 1 within the inflammasome becomes active and cleaves IL-1B into an active form of IL-1B, a mediator of inflammation that recruits leukocytes and induces fever
  • (monomers in the inactive state; once activated, will bind with other adaptor proteins)
  • cascade of events leads to NF-kB which transcribes genes for the cytokines
17
Q

What is an inflammasom electron? Describe the mechanism of an inflammasome activation pathway

A

-a high molecular weight complex that activates inflammatory caspases and activates the cytokines of IL-1 family

Mechanism:

  • a pathogenic bacteria gets sensed by NLRP-3 (sensor) NOD-like receptor, causes a chain of events
  • recruitment of different proteins and creation of inflammasom eg initial caspase is also recruited
  • inflammasom then releases active caspase-1 (cleaves and activates particular molecules)
  • caspase-1 interacts with Pro-IL1B gene and CLEAVES it to active form of ILB1 ( active)
  • secretion of IL1B causes acute inflammation
18
Q

What is gout and how do like NOD-like receptors cause it and how does it create an inflammason? (NLR’s)

A

-swelling and painful joints

  • uric acid crystals build up in joints; pain because of swollen+ inflamed joints
  • NODlike receptors are responsible for gout attacks therefore they will identify uric acid crystals as a DAMP + activate their pathway through signalling cascade
  • An inflammazom is created; which will cleave the proILIB to an active form , which will cause an inflammatory state ie recruitment of innate immune cells
  • adaptive immune cells
  • therefore increased permeability=====> swollen joints
19
Q

What are other types of cellular receptors?

A
  • CLR’s
  • RLR’s
  • CDS’s
  • GPCR’s
20
Q

What are CLR’s?

A

C-type lectin receptors -expressed on the plasma membrane of macrophages and dendritic cells detect fungal glycans and elicit inflammatory reactions to fungi

21
Q

What are RLR’s?

A

RIG-like receptors, named after RIG-1;

  • located in cytosol of most cell types and detect nucleic acids of viruses that replicate in cytoplasm of infected cells
  • once activated, signal pathways lead to production of type 1 interferons
22
Q

What are cytosolic DNA sensors?

A

CDC’s recognise viral DNA and induce type I interferon production

23
Q

What are GPCR’s?

A

G protein Coupled receptors on neutrophils, macrophages, macrophages and other types of leukocytes recognise short bacterial specific peptides beginning with N-formylmethionine and stimulate chemotactic responses of the cells

24
Q

What are the mechanisms of the innate immune response?

A

-Inflammation -Anti-viral defences

25
Q

Describe the mechanism of acute inflammation

A

1) Dilation of small vessels leading to an increase in blood flow
2) Increased permeability of the microvasculature enabling plasma proteins and leukocytes to leave the circulation and allowing entry of immune cells
3) Emigration of the leukocytes from the microcirculation, their accumulation in the focus of injury and their activation to eliminate the offending agent.

26
Q

When does inflammation occur?

A
  • protective
  • triggered when pro-inflammatory mediators are released from preformed stores or produced in response to an infectious/traumatic agent.
  • 5 signs
27
Q

What happens when viral nucleic acids are recognised by TLRs?

A
  • when they are recognised by TLRs’s the infected cells or a particular type of dendritic cell secretes cytokines that are part of the Type I interferon family
  • Production of Type I interferons has two efffects
  1. Activates enzymes that degrade viral nucleic acids and inhibit viral replication
  2. Enhances ability of NK cells to kill the infected cell
28
Q

Describe the mechanism of antiviral defences

A
  • Virus infects the cell
  • causes production and release of IFN Type I
  • IFN receptors causes a signalling cascade :

Effects:

  • Inhibition of viral gene expression ie inhibitory factors are produced that stop replication of nucleic acid
  • Produce RNAase ie causes degradation of viral RNA and detection of nucleic acids of virus
  • inhibition of protein synthesis
  • inhibition of viral replication in the antiviral state
  • inhibition of viral gene expression and virion assembly ; prevents virus from integrating its DNA into host
29
Q

What is the complement system?

A

enhances the ability of antibodies and phagocytes to

  • promote inflammation
  • attack pathogen’s cell membrane
    *
30
Q

What are the three complement pathways?

A
  1. Classical pathway: initiated by antigen-antibody complexes and certain negatively charged structures
  2. Alternative pathway: activated by several molecules on microbial surfaces
  3. Mannan-Binding Lectin pathway (MBL): activated by particular carb structures on microbes

once activated, complement protein functions as a proteolytic enzyme to cleave other complement proteins

while initiation pathways may be different, the late stages of the pathway are the same

31
Q

Describe the Classic Pathway

A
  • activated by recognition of antibodies
  • this triggers complement pathway
  • results in activation of C3
32
Q

What is the alternative pathway?

A
  • always on
  • constant dissociation of C3 molecules at a point of time when they dissociate and detect a pathogen; alternative pathway gets activated
33
Q

Describe the LECTIN BINDING PATHWAY

A
  • some pathogens have a particular glycoprotein on their surface; once recognised activation of C3 occurs
  • this activates C3a and C3b

Infection Term 4 (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions