principles of innate immunity Flashcards
1
Q
insect immunity
A
- innate immunity only due to open circulation
- main function of immune system is to localise infection
- not possible here
- as soon as microorganism has entered body it has access to the whole organism
2
Q
principles of innate immunity
A
- relies on recognition of self and non-self
- involves barriers to infection and the cells and proteins beneath them
- initial response to infections
- cells and humoral factors
- self/non-self discrimination
3
Q
innate vs adaptive immunity
A
- adaptive invovled in delayed and more specific responses
- antigen specific T/B cells
- recognition of non-self by specific receptors
- specificty and memory
- innate and adaptive systems must work together
4
Q
cells involved in innate immunity
A
- macrophages
- dendritic cells
- neutrophils
- natural killer cells
5
Q
local innate defence mechanisms
A
- resident cells with the ability to recruit
- tissue macrophages, DCs
- recruited cells
- neturophils, monocytes/macrophages, platelets
- majority of blood cells are phagoytic cells that can be recruited
- humoral factors
- complement, acute-phase proteins, clotting factors, cytokines
6
Q
monocytes
A
- circulating lymphocytes in blood that can be recruited and differentiate into macrophages
7
Q
insect clotting factors
A
- activated immediately to localise the infection
8
Q
macrophages
A
- in every tissue
- professional phagocytic APCs
- recognise and kill non-self and modified self (aged cells marked for phagocytosis)
- can release cytokines
- ROS/RNS production
9
Q
neutrophils
A
- circulate in blood
- resting until recruited to tissues by macrophages
- professional phagocytes
- ROS/RNS and antimicrobial peptide production
10
Q
dendritic cells
A
- specialised APCs
- polarise immune response
- Th1/Th2
- also ROS
- interferon cytokines
11
Q
natural killer cells
A
- recognise cells that do not express MHC or MHC-like molecules
12
Q
phagocytosis
A
- internalisation of cells, cell fragments, protein aggregates and foreign bodies
- particles >1mm diameter
- removal of debris after tissue damage, removal of apoptoic cells, destruciton of pathogens
- important part of pathogen killing in early infection
13
Q
4 stages of phagocytosis
A
- recognition of self/non-self
- directly or via opsonisation
- signal transduction
- membrane and cytoplasmic changes, enzyme secretion, degranulation, respiratory burst
- internalisation
- membrane fusion
- degradation
- phagolysosome
14
Q
recognition of non-self
A
- direct recognition
- PAMPs and PRRs
- opsonisation
- macrophage cell surface Fc receptors and complement receptors
- bind antibody (IgG) or C3b
- specific pathogen recognition mediated by antibodies
15
Q
direct recognition
A
- macrophages and DCs
- PRRs recognise PAMPs
- LPS, peptidoglycan, RNA/DNA
- genomic material → viruses
