4 Innate immunity and recognition Flashcards
How do Neutrophils/macrophages Recognise microbial particles
Possess germline-encoded receptors that are nonclonals
PAM (Patteren recognition) receptors recognise ‘patterns’
bacterial cell wall made of
- lipid part of LPS
- LPS must be delivered by LBP
- LPS + LBP + CD14 needs a 3rd protein to activate the cascade = toll like receptors
what happens after transcription
tumour necrosis factor (TNF) respiratory burst
what activates the transcription factors
LPS signalling system. The diagram shows the receptors and signal transduction pathway
by which LPS (structure shown in inset)
Recognition by
- ‘Antibodies’, Opsonins
- Complement system
- viral recognition - interferon
Oponins types
specific and non-specific
specific opsonin types
antibodies
non-specific opsonins
> complement system > fibronectin > lectins > fibrinogen > C-reactive proteins
what is recognition/processing driven by - opsonise
Fc receptors
engulf pathogen through invagination and destroy
Complement system
Complement activation (labelling + lysis) Immune adherence
Viral recognition – interferon
Generate signals that will protect other cells
what do TLRs bind
all bind to different things - their specific pattern
TLR recognition
recognise PAMPs
PAMPs activated, then many cytokines are released
what does the complement do
flags the pathogen - opsonises it for destruction
Viral recognition – interferon
cell attacked by a virus, virus replicate in cell = kills cell
cell produces interferon - secreted out of cell and bind to receptor in cell next to it = tells cell next to it to be prepared to protect self
Generate signals that will protect other cells
Recognition mechanisms
- virus via interferon
phagocytosis mechanisms: - PAMs via toll receptors
- antibodies via Fc receptors phagocytosis
- opsonins via antibodies/Fc receptors = immune adherence
Effector mechanisms
- PAMs via toll receptors
- antibodies via Fc receptors
- complement
- NK cells
Recognition/processing driven by Toll receptors (driven by toll receptors)
- recognition
- uptake
- processing
- gene activation/deletion
= response
Innate I.R. Effector mechanisms -Complement activation (labelling + lysis)
- immune adherence (mast cells, neutrophils, macrophages)
- anaphylatoxins (telling all in area there is an attack, attract neutrophils and mast C and macrophages)
- membrane lysis
where is the natural killer cell made
Bone marrow-derived cells resemble lymphocytes
what do natural killer cells not make
clonally distributed antigen receptors
what do natural killer cells do
release their preformed cytotoxic granules and kill cells infected by viruses or by some intracellular bacteria
what do natural killer cells recognise
- antibodies via Fc receptors – granule release
- activator receptors (CD2, integrins) – cell activation, IFN-gamma
- inhibitory receptors (MHC dependent) – granule release (perforin, granzyme) cell death
