3 - Innate immunity Flashcards
How are PAMPs and DAMPs recognised?
using pattern recognition receptors (PRRs)
How do NK cells detect ‘self’?
using MHC Class I specific receptors
What phagocytic cells are part of the innate immune system?
macrophages and neutrophils
What is the most common leukocyte?
neutrophils
Where are the neutrophils and macrophages in the body?
neutrophils - circulate in the blood then migrate to tissues
macrophages - dispersed throughout the tissues
What are the 4 things that neutrophils need to do to fight infection?
- move from the circulation into the tissues to the sight of infection (diapedesis and chemotaxis)
- bind to the pathogen
- phagocytose pathogen
- kill pathogen
What are opsonins?
proteins that act as ‘adapter molecules’, which bind to the pathogen and link it to the receptors present on the phagocytes
How else to neutrophils help stop the spread of infection?
NETs (neutrophil extracellular traps) - immobilise extracellular bacteria
What is the difference between macrophages and monocytes?
monocytes leave the circulation and differentiate into monocytes
macrophages>monocytes (in terms of size)
have lysosomes and PRRs
What is the function of macrophages?
- phagocytosis
- signal infection by releasing soluble mediators (alarm cytokines) (this helps to recruit other cells and activate subsequent adaptive immune system)
There are 2 types of interferons. Which are produced by the immune cells?
type 2
What effects do the following cytokines have? IL-1 TNF-α IL-6 IL-8 IL-12
IL-1 : alarm cytokine (fever)
TNF-α : alarm cytokine
IL-6 : acute phase proteins, acts over long distances
IL-8 : chemotactic for neutrophils
IL-12 : directs adaptive immune system, activate NK cells
What causes septic shock?
massive release of alarm cytokines by activated macrophages
What are the consequences of septic shock?
increased vascular permeability and severe drop in BP
Where are the components of complements made?
mainly in the liver, but can also be produced by monocytes/macrophages
(synthesised as inactive precursors and become activated enzymes)
(it is a cascade, so one enzyme catalyses the cleavage of lots of molecules down the chain, by converting the next molecule into an activated enzyme)
