Innate immunity: pathogen recognition

Question 1

MAMPs

Answer 1

Microbe associated molecular patterns
-conserved by microbes
-distinct from self
-critical for pathogen’s survival/funct

eg. bact: LPS (gram -ve), flagellins, N-formylated prots, unmeth cpG in DNA
fungi: chitin, beta-glucans, PG
viruses: dsRNA
protozoa: mannose-rich glycans, GPI-linked prots

Question 2

DAMPs

Answer 2

Damage associated molecular patterns
-host components (should be inside cell) released during cell damage

eg. DNA, mitochondrial components, frags of extracellular matrix, uric acid

Question 3

Classes of pathogen recognition receptors (PRRs)

Answer 3

Soluble receptors (eg. mannose-binding lectin)
Membrane receptors (eg. Toll-like receptors)
Cytoplasmic receptors (eg. NOD-like receptors)

Question 4

NOD-like receptors

Answer 4

cytoplasmic receptors which recognise bacterial and viral components released by phagocytes into the cytoplasm (eg. peptidoglycan fragments, viral RNA)
-trigger assembly of inflammosomes
-signal to nucleus to activate transcription of cytokines

Question 5

Toll-like receptors

Answer 5

membrane-bound (eg. cell surface, endosomal) receptors which sense pathogen components and signal, triggering change in cell behaviour
-active as dimers
-eg. TLR-4 recognises LPS, TLR-3 recognises dsRNA