2: Host Defences Flashcards
What are the stages of innate immune function? (3 stages)
- Recognition (of microbes and damaged cells)
- Activation (of mechanisms)
- Elimination (of unwanted substances)
What happens in the recognition stage of innate immune function?
Cells from innate immune system (PRRs) recognise specific microbial components (PAMPs and DAMPs)
What are PAMPs?
Pathogen assoc molecular patterns
Component derived from and sit on bacteria
What are DAMPs?
Damage assoc molecular patterns
Component derived from and sit on injured / necrotic cells
Recognised by leukocytes
What are PRR’s?
Pattern Recognition Receptors
They recognise the PAMPs and DAMPs
Where are PRRs located?
In cellular compartments where microbes might be present e.g plasma memb
What are the types of PRR? (3 types) (general)
- Intracellular
- Extracellular
- Secreted (induce complement cascade)
What do PRRs trigger the innate immune response to do? (6 things)
- Initiate opsonisation
- Activate complement prot
- Induce phagocytosis
- Activate inflamm mediators
- Secrete anti-inflamm and pro-inflamm cytokines
- Induce apoptosis
What are the types of PRRs (2 types) (more specific)
- Toll Like Receptors (TLRs)
2. NOD Like Receptors (NLRs)
What are Toll Like Receptors?
A type of PRR
Activated –> initiate cascade of events –> activates transcription factors
What are NOD Like Receptors?
A type of PRR
Cytosolic receptors that recognise cell walls of pathogens
Where are NOD Like Receptors found?
Cytoplasm
What is the complement system?
Complex set of enzymes and non-enzymatic proteins
Provide essential functions to innate and adaptive immunity
What are the different complement pathways? (3 types)
- Classical
- Alternative
- Mannan-binding Lectin (MBL)
What is the classical complement pathway initiated by?
Antigen-antibody complexes
Certain -vely charged structures
