Innate immune protection Flashcards
How quickly does innate, early induced and acquired immunity responses occur
Innate: 0-4 hours
Early induced: 4-96 hours
Acquired immunity: 96 hours<
What are the components of the innate immune system
Physical-skin, GI tract (low pH bacteria dislike, activate enzyme), respiratory tract, mucosal epithelia
Secreted compounds-antibacterial compound, complement, natural antibodies, cytokines
Cellular components-phagocytes, NK cells
What does the innate immune system recognise a pathogen using
Innate system uses its Pattern Recognition Receptors to recognise Pathogen Asscoiated Molecular Pattern
What are the different types of PRR
Collectin in serum
Toll like receptors=membrane bound. TLR 1+2=gram+, TLR3=RNA virus, TLR 4=gram-, TLR5=motile bacteria/parasite, TLR6=mycoplasma
NOD like receptors=cytoplasm, recognise gram+ and gram- bacteria. When PRR recognise PAMP, signal sent to upregulate important molecules. NOD1=gamma glutamyl diamine, NOD2=muramyl dipeptide
What are the effective mechanisms of the innate immune response
complement, phagocytosis+killing, cytokines, activation of adaptive immunity
Complement what is it and how does it operate
series of proteins that circulate in blood and tissue fluids. Operates via cascade.
How is C3 convertase activated and what does it do
ref. notes. C3 activates convertase
Which cells are used for phagocytosis
monocyte/macrophage, neutrophils
How does the killing mechanism for neutrophils and macrophages work
After phagocytosis, increase in O2 uptake=respiratory burst->O2 reduced by NADPH oxidase to form hydroxyl radicals and hypochlorite->DNA damage and alterations in bacterial membranes
L-arginine to L-citrulline generates NO radicals (catalysed by enzyme inducible nitric oxide synthase) induced by cytokines and bacterial components. NO causes DNA damage and alterations in bacterial memb
What do cytokines do in the innate immune system
act as intracellular messengers, bind to specific receptors and can be activated/deactivating
What are chemokines and what do they do
class of cytokines with chemoattractant properties Promote inflammation by enabling cells to adhere to surface of blood vessels and migrate to infected tissues..Produced by endothelial cells and macrophages
What do interferons do
Type 1 interferons (IFNalpha an IFNbeta) produced in response to virally infected cells->NK cells kill virally infected cells and tumour cells, responsive to TNFalpha and IL-12, produce IFNgamma which activates thee macrophages
Type 2 interferon activate acrophage from antimicrobial killing
What does a critical cytokine do
activates macrophages, upregulates MHC molecules together iwth IL-12 stimulates differentiation of CD4 Th1 cells
Draw out how innate immunity and the adaptive immune response work together
ref. notes
What do dendritic cells do
Mature DC present antigen to activate T cells
Immature DC displays lots of PRR->maturation happens when PRR recognisese, MHC and costimulatory molecules becomes exposed for cell activation
