Flashcards in Response To Pathogens Deck (18)
What are the essential functions of the innate immune system?
Initial rapid response to microbes
Elimination of damaged cells and initiation of tissue repair
Stimulation of adaptive immune system
What is used by the innate immune system to recognise non-self?
Pattern recognition receptors (PRRs) on host cells recognise Pathogen associated Molecular Patterns (PAMPs) on pathogen
Why are PAMPs suited to being recognised by the innate immune system?
1) conserved among classes of micro organisms
2) products of micro organisms that differ from humans
3) essential roles in structure or function of the microbe
What are the types of PAMPs?
Bacterial PAMPs often components of cell wall; lipopolysaccharides, peptidoglycan, lipoteichoic acids and cell
β glucan for fungal
Viral nucleic acids
What are the three main types of PRR?
Signalling : toll-like, nod-like and RIG-like
Where are Toll-like receptors found?
Location reflects their ligand:
TLR that recognises extracellular are on cell surface
TLR that recognises intracellular are in the endosome
What is the effect of TLR signalling?
What are some deficiencies of TLRs?
all are associated with severe infections
Where are NOD like receptors found?
Intracellular soluble proteins
What are the four families of NOD-like receptor?
What do they cause?
Regulate activation of Caspase-1 and form part of the inflammasome
What are RIG-like receptors?
Soluble intracellular receptors that recognise the dsRNA of viruses in the cytoplasm
RIG-1, MDA5 and LGP2
What are the secreted PRRs?
Anti microbial peptides - α and β defensin
C reactive protein
Mannose binding lectin
What are the endocytic PRRs?
Mannose receptors on macrophages and neutrophils
Scavenger receptors on macrophages
What cells express PRRs?
Macrophages and dendritic cells
Some non-haematopoietic cells
What are the vascular effects of pattern recognition?
Why do they happen?
Cytokines from dendritic cells and resident cells induce changes in endothelial cell vessel walls and allow infiltration of cells and plasma proteins to site of infection
Increased vascular diameter: heat and redness
Increased vascular permeability: swelling and pain
What is chronic granulomatosus disease?
How is it diagnosed?
Characterised by repeat infections
Due to delayed neutrophil apoptosis and defective superoxide production. Mutations in components of superoxide complex
FBC showed neutropenia, CRP/ESR show inflammation and test oxidative function
How is complement involved in an antibacterial response?
Classical pathway opsonises the pathogen for phagocytosis
Also forms membrane attach complex to make holes in the membrane