Innate immunity Flashcards
(17 cards)
Recall physical barriers used by the immune system
skin
mucous - goblet cells
acid
cilia
Recall chemical barriers used by the immune system
Body temp
pH
chemical mediators - lysozyme, interferons, complement
inflammation - increased permeability - cell out of blood into site of infection
phagocytosis
What are cytokines, and their features
small secreted proteins messengers of immune system act locally short half life - v. powerful cell to cell communication
Type of cytokine and their function
interleukin - between leukocytes interferon - anti-viral chemokine chemotaxis - cell movement cytotoxic tumour necrosis factor growth factors - proliferation and differentiation
cytokine pathway
macrophage activated
granule released - autocrine/paracrine/endocrine
bind specific receptor
up/down regulate gene
How are dendritic cells involved with complement
recognise microbial patterns and secrete cytokines
capture pathogens - lymph node - present antigens to adaptive immune system
What is complement
series 30 proteins, glycoproteins
components produced in liver
complements specific antibody
Recall the complement pathways
classic - antibody bound antigen - cleaved part is pro-inf by degrading mast cell
lectin - protein binds to carbohydrate on bacterial surface
alternative pathway - bacterial surfaces themselves
How is complement controlled
liability - short half life
dilution of components in biological fluids
membrane bound and circulating regulatory proteins
functions of complement
lysis
opsonisation
activation inf response
clearance of immune complex - complement receptors
acute phase response
accompanies innate immunity
C-Reactive protein (CRP) - c polysaccharide of pneumococcus - activates complement
Mannan binding lectin (MBL) - activate complement
complement
fibrinogen
list cell types in innate immunity
neutrophil eosinophil basophil monocyte/macrophage mast cell dendritic cell natural killer cell
what are the phagocytic cells
neutrophil - short life, first cells recruited
macrophage - in tissue, cytokines, APC
What are the actions of neutrophils
diapedesis and chemotaxis
opsonisation - coat microbes protein for phagocytosis (antibody and complement) - neutrophil bind to opsonin
killing methods - oxygen-independent (enzymes, lysozyme, hydrolytic enzyme, defensins) oxygen dependant (superoxide anion, hydrogen peroxide, nitric oxide etc)
extracellular traps - release protein and chromatin - stop migration, enhance phagocytosis
what are the actions of macrophages
PRR - carb on bacteria etc
bacteria binding - cytokines
phagocytosis
What are the actions of mast cells
histamine and inf mediators eg cytokines
mucosal/connective tissue (skin, peritoneal cavity, near BV)
phagocytosis - PRR
activated by complement
vasodilation
what are the actions of natural killer (NK) cells
not specific
activating and inhibitory receptors - self - inhibition or missing self and induced self by stress - activating
antibody dependant cell mediated cytotoxicity
defence against tumour/viral
