Lectur 13: Innate Mechanisms Flashcards
Again, what are the five innate immune mechanisms
- inflammation
- cellular recruitment
- phagocytosis
- oxidative burst
- NETs
What is phagocytosis
Process where innate immune cells eat pathogens
What cells use phagocytosis
Macrophages
Dendritic cells
Neutrophils
What is a phagosome
Membrane bound vesicle where the pathogen is caught
What is a phagolysome
A phagosome fused with a lysosome
What happens after the pathogen is caught in the phagosome
Fuses with lysosome vesicles which exposes pathogen to cytotoxins and anti-microbial peptides
What other processes occur within a phagolysome
- acidification
- enzymes
- anti-microbial peptides
- metabolic competitors
- reactive oxygen and nitrogen
How do phagocytes bind with pathogens
Receptors on the phagocytes recognizing residues on the target pathogen
Where is most of the digestive punch of phagocytosis
The lysosome
What are lysosomes
Membrane bound vesicles located within the cytoplasm
Why don’t we eat ourselves
Most enzymes are not active at a normal body pH of 7, the pH has to be acidic
What is oxidative burst used for
Some pathogens are resistant to killing by lysosomal contents
What is oxidative burst
Phagocytes are able to use a series of enzymes to generate reactive oxygen and nitrogen
For reactive oxygen what does the system revolve around
Superoxide
What is responsible for the generation of ROS
NADPH
What kind of reactivity and half-lives do ROS have
Extremely reactive thus have short half life’s
What are neutrophils extracellular traps
Some neutrophils can release their DNA and spread it around like a net to catch pathogens
How toxic are NETs
Very cytotoxic and can cause host damage
How are lysosomes made? (5 steps)
- proteins that are going into the lysosome are tagged by M6P residue
- this bundle binds to M6P receptor in the endoplasmic reticulum which is in the Golgi apparatus
- fuse with late endosomes
- this late endosome pumps H+ lowering pH
- at low pH the enzymes dissociate from M6P and become activated
