Lecture 2

Question 1

What are the different types of PRRs?

Answer 1

1. membrane bound phagocytic receptor
2. membrane bound signalling receptor
3. soluble cytoplasmic signalling receptors
4. soluble protein in serum

Question 2

What are the different types of PRRs?

Answer 2

1. membrane bound phagocytic receptor (mannose)
2. membrane bound signalling receptor (TLR)
3. soluble cytoplasmic signalling receptors (NOD)
4. soluble protein in serum

Question 3

What is the structure and location of Toll-like receptors/intracellular PRRs?

Answer 3

TLR: leucine rich domain (ligand that interacts with pathogen), trans-membrane domain, Toll-IL-1 (TIR) domain (signalling)
- located in the plasma membrane of cells, or endosome membrane

Question 4

What are the key differences between innate and adaptive receptors?

Answer 4

innate: germline encoded, recognize molecular motifs found in LARGE groups of pathogens
adaptive: assembled from somatic recombination, recognizes fine molecular details

Question 5

What are the two categories of membrane bound phagocytic receptors? What do they do?

Answer 5

opsonic: indirect recognition (bind to complement/igG that is already bound to the pathogen)
non-opsonic: bind directly to the surface

both initiate signalling cascades for phagocytosis

Question 6

what is the first cell to detect infection?

Answer 6

tissue resident macrophage

Question 7

What is the function of TLRs?

Answer 7

either leads to proinflammatory cytokines or type I IFNs

Question 8

If a TLR is on the plasma membrane, what does it recognize? If a TLR is in an endosome, what does it recognize?

Answer 8

• pathogens in the tissue
• pathogens that have entered the cell by phago/endocytosis

Question 9

What is NOD-like receptor?

Answer 9

• cytoplasmic proteins that are intracellular sensors of bacterial infection
• activates transcription factors that lead to inflammatory cytokines

Question 10

What is RIG-I-like receptor?

Answer 10

detect viral RNAs in the cytoplasm

Question 11

What is cGAS-STING receptor?

Answer 11

detects dsDNA in the cytoplasm

Question 12

What are three important soluble PRRs? What do they recognize?

Answer 12

• C-reactive protein, phosphocholine
  Mannose-binding lectin, mannose sugars
  LPS binding protein, LPS (by bringing it to CD14– MP