Innate 4 point summary
- Inflammatory response
- Complement
- Interferons
- Leukocytes
Inflammation
recognition: PAMPs bind to PRR e.g. TLR,CLR, NOD
Activation innate: macrophages/ mast cells
inflammatory mediators: mast cells
5 signs of inflammation
- Heat 2. Redness 3.Pain 4. Swelling 5.Loss of function
example innate recognition by TLR
TLR-3 Ligand:ds RNA (found only in virus)
TLR-4 dimer: LPS (gram-ve bacteria)
TLR stimulation can = cell activation, activates…
cell secretes cytokine & chemokines
- inflammation
- recruitment more phagocytes (increases intracellular killing)
Acidification mechanism in pattern recognition
pH= ~3.5-4, bacteriostatic or bactericidal
Toxic oxygen derived products mechanism in pattern recognition
superoxide O2-, H2O2, singlet oxygen 102, Hydroxy radical *OH, hypophalite OCl-
Antimicrobial proteins mechanism in pattern recognition
defensins & cationic proteins
Enzymes mechanism in pattern recognition
lysozyme: dissolves cell walls of some gram+ve bacteria. Acid hydrolases: further digest bacteria
Competitors mechanism in pattern recognition
Lactoferrin (binds Fe) & VitB12 - binding protein
Steps of phagocytosis
Recognition: TLR - binding to PAMP present on pathogen
- chemotaxis & adherence of microbe to phagocyte
- Pseudopod formation
- Ingestion of microbe by phagocyte
- Phagosome:
- Phagolysosome formation
- Digestion: of ingested microbes of enzymes
- formation of residual body containing digestible material
- Discharge of waste materials
Complement (Alternative & MBL pathway
Bacterium is coated w/ complement by alternative & MBL pathways
When only C3b binds CR1, bacteria are not phagocytosed
C5a can activate macrophages to phagocyose via CR1
Complement C5b onwards
C5b binds C6 & C7, C5b67 complexes bind to membrane via C7, C8 binds to complex & inserts into cell membrane, C9 molecules bind to complex & polymerise, 10-16 moelcules of C9 bind to form a pore in membrane
- results of PRR
- Cell activation 2. Cell recruitment 3. Bacteria killing
