Recognition and signalling

Question 1

Describe what is meant by PAMP (2)

Answer 1

• pathogen associated molecular pattern
  -the features a pathogen carries that distinguishes it from human cells

Question 2

Describe the process that leads to bacteria being taken up into the phagolysosome (2)

Answer 2

-fMet-Leu-Phe peptides to activate Rac granules
-activating cell to take bacteria in

Question 3

Describe how, once engulfed, a bacteria is killed [5]

Answer 3

• granules in cytoplasm merge with phagosome
  -Rac induces the assembly of NAPDH oxidase
  -NAPDH is oxidised
• increases the reactivity
• leads to decrease in pH in phagolysosome

Question 4

Define the term respiratory burst

Answer 4

release of toxic oxygen derived products

Question 5

Describe how GPCR leads to respiratory burst [5]

Answer 5

• ligand binds to activating GPCR
• GDP to GTP
• G protein to a and BY subunits
  -both activate other proteins (Rac,cdc42, rho)
  -leads to respiratory burst (chemotaxis)

Question 6

Describe how eosinophils target bacteria

Answer 6

traps made from mitochondrial DNA

Question 7

How do eosinophils target bacteria [2]

Answer 7

• degranulation
• lysozyme contents released into the periphery

Question 8

The activation of PAMPs can lead to what 3 functions?

Answer 8

• phagocytosis
• secretion of cytokines
• production of type one IF

Question 9

Briefly describe toll-like receptors [5]

Answer 9

• all have leucine rich motif
• lipoppetide binds
• dimerisation of receptors activates TLR
• activation causes the signalling domain to come together
  -can be Herero/homodimers

Question 10

Where are RIG-like receptors found

Answer 10

cytoplasm

Question 11

What id NFkB

Answer 11

a transcription factor for inflammatory cytokines/ type 1 interferons

Question 12

What is a CARD?

Answer 12

caspase recruitment domain

Question 13

Describe how NOD like receptors lead to NFkB activation[5]

Answer 13

• CARD domain
• activated by bacterial ligand
• recruitment and ubiquitination of RIP 2
• activates TAK1
• phosphorylisation and activation of NfKB

Question 14

Describe how nod-like receptor proteins leads to the killing of pathogenic cells [7]

Answer 14

• activated by PAMPs
• oligoermerise into inflammasome
  -recruits and activates caspase 1
• cleaves molecules and activates them
• forms pore
• releases of inter-leukins
• induces the killing of cells