Lecture 17 Flashcards
What is the PAMP on flagellated bacteria?
Flagellin
What is the PAMP on gram -ve bacteria?
Lipopollysaccharides
What is the PAMP on gram positive bacteria?
Peptidoglycan
What is the PAMP on the surface of fungi?
Zymosan
What is the PAMP on viruses?
ssRNA
What are the 4 types of Pattern Recognition Receptors?
Toll like receptors (TLR)
NOD like receptors (NLR)
Rig-I like receptors (RLR)
C-type lectin receptors (CLR)
True or false: Pattern recognition receptors can only recognise one type of PAMP
False: Receptors can recognise more than one PAMP
Where are three places that pattern recognition receptors are located?
On the cytosolic membrane
On the endosomes (vesicles)
In the cytoplasm
True or false: toll like receptors are only conserved in primates and were first discovered in humans
False: Evolutionarily conserved throughout evolution and were first discovered in Drosophila
What are the two main Rig-I like receptors? Where are they located? What do they recognise?
RIG-I and MDA5
Intracytoplasmic
Recognise dsRNA
What do G-type lectin receptors bind to?
Carbohydrates
Describe the two TLR signalling pathways responding to gram -ve bacteria and what the outcomes are
- TLR4 receptor recognises LPS on gram -ve bacteria. Adaptor molecule MyD88 causes downstream effects which causes the release of an inhibitor from the transcription factor NFKB. NFKB turns on gene expression to produce inflammatory cytokines- IL6, TNF, IL1, IL8
- TLR4 receptor recognises LPS on gram -ve bacteria. Adaptor molecules Mal and TRIF cause downstream effects to cause:
a. NFKB to be released and turn on expression of inflam cytokines
b. IRF3 release to turn gene expression of inflam cytokines- IFNalpha and IFNbeta.
What transcription factors are activated when Rig-I like receptors bind dsRNA?
NFKB and IRF3
What type of receptor recognises danger/non-danger?
NOD-like receptors (NLRs)
Where are NOD-like receptors located in the cell?
Cytosol
What do NOD-like receptors recognise?
Viruses and bacteria
NOD-like receptors recognise:
a. Pattern associated molecular patterns (PAMPs)
b. Danger associated molecular patters (DAMPs)
c. Both DAMPs and PAMPs
d. none of the above
c. Both DAMPs and PAMPs
What are 4 examples of DAMPs? What do they all mean?
Microbial peptides
Crystals
Molecules from dying cells
Molecules from stressed cells
All indicate that cells are under attack
Why is there aluminium in vaccines?
Aluminium activates the inflammasome
Why does gout have so much inflammation as a symptom of the disease?
Uric acid crystal build up in the joints. The crystals activate the inflammasome which causes the intense inflammation
Why is the inflammasome a target for autoimmune diseases?
Many autoimmune diseases cause lots of inflammation. Want to decrease this inflammation= target the inflammasome
What is NLRP and why and how is it created in response to PAMPs?
NLRP is a subunit of the inflammasome. When transcription factors NFKB are turned on, one of the genes it activates to be expressed is the NLRP gene. This is a ‘just incase’ response incase DAMPs are recognised and the inflammasome is required.
What is the structure of the inflammasome? What is the function of the three parts?
Top part: NLRP- the part that recognises danger
Middle part: structural proteins ASC and Cardinal
Bottom part: Capsase, the action part that cleaves the pro-interleukens
What are the two pre-cursor cytokines that are expressed in response to danger?
Pro-IL1
pro-IL18
