IMMUNITY REVISION Flashcards
what causes the cardinal signs of inflammation
caused by histamine release from mast cells, basophils and platelets, binds to histamine receptors and leads to vasodilation and exudation
what are the cardinal signs of inflamamtion
rubor
calor
dolor
tumour
functio laesa
what are the different barrier defences
flow of air or fluid
enzymes
low pH
defensins
normal microbia
tissue resident immune cells
cilitated cell
goblet cells
epithelial tight junctions
flow of air or fluid
reduces the change of mucroorganisms attaching
enzymes
secretions contain antimicrobial enzymes
lysozyme in tears
low ph
restricts which oathogens can survive if ingested
defensins
antimicrobial peptides disrupt the clel membranes and virus envelopes
normal microbia
outcompete potentiall harmful rganisms
tissue resident immune cells
recognsie
engulf
phagocytose and ill pathogens
cilitated cells
move mucus along to flush out thepathogens
goblet cells
produce mucus which acts as a sticky barrier
epithelial cells tight junctions
restrict movement of microorganisms deep into the tissue
migration of neutrophils in inflmmation
- Margination: cells line up against the endothelium
- Rolling: close contact with and roll along the endothelium
- Adhesion: connecting to the endothelial wall
- Emigration: cells move through the vessel wall to the affected area
what happens when no microbes are present
- DAMPs/PAMPs bind to PRR’s
- Activate cells
- Induce inflammatory cytokine release
- Trigger inflammation
what are the different types of PRR’s
toll like receptors
phagocytic receptors
NOD and RIG like receptors
toll like receptors
external or endosomal
change gene transcription and cytokine release
which toll like receptors are on the plasma membrane
TLR4
TLR5
TLR2
TLR1/6
which toll like receptors are endosomal
TLR3
TLR7
TLR8
TLR9
what binds to TLR 4
LPS
what binds to TLR 5
flagellin
what binds to TLR2, 1 and 6
lipoproteins
what binds to TLR 3
dsRNA
wat inds to TLR 7 and 8
ssRNA
what binds to TLR9
CpG DNA
phagocytic receptors
external
induce the uptake of pathogens into the endosomes and killing of the pathogen
what are the different phagocytic receptor
complement
savenger
mannose
Fc
C type lectin
NOD and RIG like receptors
cytoplasmic
change gene transcription
and cytokine release
extracellular TLR signalling
- Binding of PAMP to PRR
- Signal to nucleus
- Adaptors containing TIR domains transmit message to cytoplasm
- NFKB assembles and binds to DNA
- Instructs cells to produce new proteins which initiate next stage
endosomal TLR signalling
- Recognition of a pathogen within the endosome
- Signal to the nucleus
- Adaptors containing TIR domains transmit message to cytoplasm
- Interferon response factors assemble and bind to DNA
- Instructs cells to produce new proteins: interferons which direct immune responses against viruses and intracellular bacteria
- IRF3: interferon B so antiviral response occurs
- IRF7: type 1 interferons so antiviral response occurs
NOD and RIG signalling
- Recognition of DAMP’s and PAMPs in the cytoplasm transmits signal to the nucleus
- NLR aggregate and form inflammasome
- Activates and causes release of pro-inflammatory cytokines
- RLR aggregate and activate transcription factors leading to production of new proteins including type 1 interferons
macrophages and pathogens
- Pathogen recognized by the PRR and macrophages activated
- Phagocytosis induced
- Pathogen is either internalized in a phagosome or activated macrophages make proinflammatory cytokines to attract other immune cells
- Pathogen is killed by oxidative burst and digested enzymes
how do immune cells find pathogens
where the concentration of the chemokine is the highest
neutrophil arrival
- Phagocytose similar to macrophages
- Microbes are phagocytosed into phagosomes
- Phagosomes fuse with the granules which contain antimicrobial enzymes, proteins and peptides
- Microbes killed by digestion and respiratory burst
- 3 types of granules: primary (azurophilic), secondary (specific) and tertiary (gelatinase)
- Apoptosis and netosis: respiratory burst by producing toxic oxygen species to kill the bacteria
- Netosis causes release of NETs: DNA covered in histone proteins and granule contents which trap the microbes
what happens if the pathogen isnt cleared
- Release pro-inflammatory cytokines
- Damaged blood vessels will produce bradykinins to increase vascular permeability and stimulate nerves causing pain
- Then resolves in adaptive immunity
exampels of some acute phase proteins
Acute phase proteins: serum amyloid, C-reactive, fibrinogen, mannose binding lectin
complement pathway
howdo cells recognsie intracellular moleucles
- Damage caused can be recognized by PRRs
- PAMPs released from cells can also activate innate immune cells
- Phagocyte will try and kill the bacteria by acidification and enzymatic digestion
- Some thrive and survive
- Others will penetrate cell from outside or escape from phagosomes into the cytoplasm
- When in the cytoplasm the bacterial products can be recognsied by internal PRRs
- Cytokines released to activate NK cells and adaptive immune cells
interferons
increase viral defences and reduce viral replication