3- innate Immunity: Recognition of Foreign Invaders Flashcards
How do sentinel cells recognize pathogens?
Pattern Recognition Receptors (PRRs)
The ‘alarm signals’ that are detected by sentinel cells are generated by what two things?
Pathogen-Associated Molecular Patterns (PAMPs)
Damage Associated Molecular Patterns (DAMPs) or alarmins
What are PAMPs?
Exogenous signals that consist of molecules produced by microbial invaders
What are DAMPs?
Endogenous signals that consist of molecules released by damaged, dead, or dying host cells
Recognition of pathogens by sentinel cells leads to what?
The activation of the innate immune system
What are the 4 examples of PAMPs?
1) Bacterial Lipopolysaccharides
2) Bacterial Peptidoglycans
3) Bacterial DNA
4) Viral Nucleic Acids
Lipopolysaccharides are found in gram positive or negative bacteria?
gram-negative
Peptidoglycans are found in gram positive or negative bacteria?
gram-positive
What is the most important intracellular DAMP?
HMBG1
What are the 4 types of PRRs?
Soluble
Within vesicles
Cytoplasmic
Membrane-bound
What is the most important PRR?
Toll-Like receptors (TLRs)
What are TLRs and what role do they play in innate immune response?
Transmembrane glycoprotein receptors that are present on many different cell types including sentinel cells
- play a critical role in microbial sensing by recognizing bacteria, fungi, and viruses
Which TLRs are intracellular? What do they recognize?
TLR3, 7, 8, 9, and 10
recognize viral and bacterial nucleic acids
What do cell surface TLRs recognize?
bacterial and fungal proteins, lipoproteins and LPS
German shepherd dogs suffering from inflammatory bowel disease have several single-nucleotide polymorphisms (SNPs) in which genes?
TLR4 and TLR5
suggests that their TLR4 and TLR5 have reduced ability to defend against bacterial invasion resulting in predisposition to enteric infections
