Lecture 2 Flashcards
What are the different types of PRRs?
- membrane bound phagocytic receptor
- membrane bound signalling receptor
- soluble cytoplasmic signalling receptors
- soluble protein in serum
What are the different types of PRRs?
- membrane bound phagocytic receptor (mannose)
- membrane bound signalling receptor (TLR)
- soluble cytoplasmic signalling receptors (NOD)
- soluble protein in serum
What is the structure and location of Toll-like receptors/intracellular PRRs?
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
What are the key differences between innate and adaptive receptors?
innate: germline encoded, recognize molecular motifs found in LARGE groups of pathogens
adaptive: assembled from somatic recombination, recognizes fine molecular details
What are the two categories of membrane bound phagocytic receptors? What do they do?
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
what is the first cell to detect infection?
tissue resident macrophage
What is the function of TLRs?
either leads to proinflammatory cytokines or type I IFNs
If a TLR is on the plasma membrane, what does it recognize? If a TLR is in an endosome, what does it recognize?
- pathogens in the tissue
- pathogens that have entered the cell by phago/endocytosis
What is NOD-like receptor?
- cytoplasmic proteins that are intracellular sensors of bacterial infection
- activates transcription factors that lead to inflammatory cytokines
What is RIG-I-like receptor?
detect viral RNAs in the cytoplasm
What is cGAS-STING receptor?
detects dsDNA in the cytoplasm
What are three important soluble PRRs? What do they recognize?
- C-reactive protein, phosphocholine
Mannose-binding lectin, mannose sugars
LPS binding protein, LPS (by bringing it to CD14– MP
