innate immune responce Flashcards
innate immunity composition
physical and chemical barriers
phagocytic cells
blood proteins
receptors in blood
monocytes
neutorphils
receptors in tissues
macrophages
dendritic cells
what to immune cells regoncise and with what
PAMPs on microbes
use PRR receptors
name the pattern regonicition receptors
C type lectin receptors
TLRs
Scavenger receptors
what do C type lectin receptors regonise
non self carbohydrates
what do TLRs recognsie
non self molecules
PAMPs expressed by microbes
what happens once TLR binds
generates immune response resulting in chemokine secretion
what do scavenger receptors bind to and do
non self lipids
bind and internalise LDLs
what are complement
serum proteins that need to be activated
what gets produced once complement is activated
Chemotaxins C3a C5a
C3B
MAC
what do C3a and C5a do
act like chemokines
what does C3b do
coats the bacteria
opsonisation
what do MAC do
direct cell lysis by hole in membrane
what is the process o cells leaving circulation and moving to site of infection
extravasation
explain extravasation
macrophage recognises but but cannot eliminate
intracellular signalling
secretes TNF alpha
TNF activates endothelium to express molecules on surface
makes endothelium secrete chemokines (trapped on glycosaminoglycans)
neutrophils roll on endothelial surface
chemokine receptor binds to chemokine, sends signal in cell so neutrophil thermadhere
move though gaps in endothelium
what is the listed process of extravasation
tethering singalling firmadherace chemotaxis killing
what does TNF do
activates endothelium to express molecules on the surface to make it more sticky
how does phagocytosis occur
macrophage/neutrophil uses same receptor to bind as to sence
bacteria binds to suface and is engulfed into a phagosome
other vesicles bind and form a phagolysosome
digest bacterium
some material exerted some displayed some used as energy store
what happens when a phagocyte is full
apotosis
encloses everything in plasma membrane
other phagosomes engulf fragments
what are the two mechanism of microbial killing
O2 dependant
O2 independant
what is the O2 independent pathway
use of: enzymes
protiens
pH
O2 dependant pathway
reactive oxygen intermediates
superoxides are conserved to hydrogen peroxide and then hydroxyl radical, terminates bacterial DNA
NO can cause extravasation
how are complements activated
classical- Ab bound to microbe
alternative - complment bound to microbe
lectin - MBL bound to microbe
types of C type lectin receptor
type 1 - many C type receptors
type 2 - only one C type receptor
