lecture 3 Flashcards
(24 cards)
what is produced in response to infection?
= pro-inflammatory cytokines
what IL-2 cause?
T cell proliferation
what does IL-10 cause?
anti-inflammatory
describe the appearance of neutrophils?
= multi lobulated nucleus
= pink cytoplasm
True or false.
neutrophils are long lived?
= false
- they are short lived
what is main mode of movement of neutrophils used to move from blood to the tissue through the blood vessel wall?
= trans-endothelial migration
what is trans-endothelial migration triggered by?
= triggered by po-inflammatory mediators as they promote vascular changes
describe the process involved in trans-endothelial migration of neutrophils?
1) margination of neutrophils to endothelium
2) binding of neutrophils to adhesion molecules (e.g. ICAM ) on endothelial
(Histamien & TNFalpha promote the expression of adhesion molecules)
3) migration across endothelium by diapedesis
4) movement of neutrophils within tissue via chemotaxis
5) activation of neutrophils via their PAMPs via TNFalpha
what are 3 mechanisms of neutrophil killing?
1) phagocytosis
2) degranulation
3) NETs
= neutrophils extracellular traps
what does NETs stand for?
= neutrophils extracellular traps
what happens in degranulation?
= direct killing of the extracellular pathogen
BUT
= it can lead to tissue damage and systemic inflammation
what is the purpose of NETs?
= to immobilise the pathogen
- making it easier for the pathogen to be killed by phagocytosis
+
= prevents the phagocyte migrating/moving anywhere
what is an abscess?
= collection of pus, surrounded by a membrane of spouting capillaries, neutrophils and fibroblasts
what is the acute phase response driven by?
= pro-inflammatory mediators released by macrophages (IL-1, IL-6 and TNF)
what is acute phase response mediated by?
= liver hepatocytes which produce acute phase proteins
what is the complement system?
= a family of proteins that are produce din the liver but circulate in the blood
what sort of reaction does the complete system result in?
= cascade reaction
what are 3 types of pathway involve din the complement system?
1) classical pathway
2) alternative pathway
3) myosin binding lectin pathway
what do all of these pathways do?
break down
C3 = C3a + C3b
what is the mannose binding pathway lectin triggered by?
= bacteria
what happens in the alternative pathway?
the C3b produced is highly UNSTABLE so binds to the cell surface resulting in;
(a) opsonisation
(b) triggering C5 = C5a + C5b
what does C5b promote?
= formation of the membrane attack complex
what do MACs do?
= insert themselves into pathogens membranes allowing extracellular salts and water to enter
= causing the cell to swell and burst
= LYSIS
what is the role of C5a and C3a?
= inflammation
