Lecture 3 - Early Recognition of Foreign Invaders Flashcards
What cells recognize alarm signals?
sentinel cells
What do sentinel cells have that recognize alarm signals?
pattern recognition receptors
Alarm signals are generated by what 2 things
- invading microorganisms (PAMPs)
- dead or dying host cells (DAMPs or Alarmin)
What are exogenous signals
PAMPs
What are endogenous signals
DAMPs or Alarmins
Recognition of pathogens by sentinel cells leads to activation of …
innate immune system
What are PAMPS
conserved molecular structures or patterns that occur in a diverse range of potential microbial invaders
Examples of PAMPs
- bacterial lipopolysaccharides
- bacterial peptidoglycans
- bacterial DNA
- viral nucleic acids
What is another name for LPS
endotoxin
What bacteria have LPS
gram-negative
What bacteria have peptidoglycan
gram-positive
Why is bacterial DNA a PAMP
its unmethylated
What is the PAMP in gram-negative bacteria
LPS
What is the PAMP in gram-positive bacteria
peptidoglycan
What is the PAMP in acid fast bacteria
mycolic acid
When are intracellular DAMPS generated
released when cells die
When are extracellular DAMPs generated
connective tissue is damaged
Why might damaged mitochondria from dead host cells be recognized as bacteria?
DNA resembles bacterial DNA, which is rich in unmethylated CpG
Examples of extracellular DAMPs
-hyaluronic acid
-heparan sulfate
-fibrinogen
-collagen-derived peptides
-fibronectin
-laminin
-elastin
Examples of intracellular DAMPs
-HMGB1
-uric acid
-chromatin
-andenosine
-galectin
-S100 proteins
-cathelicinds
-defensins
-N-formyl peptides
-lactoferrin
-heat-shock proteins
What is an important intracellular DAMP
HMGB1
What is the main affect of HMGB1?
inflammation; tissue damage
What is the adverse effect of too much HMGB1
shock
What types of PRRs soluble
-collectins
-ficolins
-complement
-pentraxins
What PRRs are within vesicles
-TLR 3, 7, 8, 9
Whaat PRRs are cytoplasmic
-Rig-1
-NOD-like
-peptidoglycan receptors
-DNA receptors
What PRRs are membrane-bound
-TLRs
-Lectins
-Mannose receptor
-Langerin
-Dectins
-Scavenger receptors
-intergrins
What are the most important PPRs
TLRs
What type of receptors are TLRs
transmembrane proteins
List the 3 PRR receptors
- toll-like receptors
- retinoic acid inducible gene (RIG)-1like receptors
- nucelotide-binding oligomerization domain (NOD)-like receptors (NLRs)