Cell Biology and the Immune System Flashcards
What are tissue macrophages derived from?
Monocytes
What are monocytes?
Recruited to infected and damaged tissues where upon they differentiate into additional macrophages.
What can macrophages bind to?
The microorganism or bind molecules that have opsinised (coated) the microorganism
How does receptor signalling initiate phagocytosis?
IgG receptor binds IgG opsinised microorganisms. Clustering causes phosphorylation of intracellular tyrosine motifs by Src protein kinases. Sykinase is recruited and promotes phagocytosis.
How does the phagosome form?
Rac and cdc42 GTPases interact with Wiskott-aldrich syndrome protein which activates Arp2/3 promoting actin filament formaiton
What do Rab5 and Rab7 do as the phagosome matures?
Recruit proteins onto the membrane as the phagosomme moves towards the nucleus
name 5 antimicrobial activities?
- nutrient depravation
- hydrolases
- reactive oxygen and nitrogen
- Membrane permeabilisation by defensins
- Acidification
How has M. tuberculosis adapted to evade the macrophage?
Arrests phagosome maturation
How does L. monocytogenes evade the immune system?
Modifies and escapes phagosomes
by creating pores through which H+ and Ca2+ can escape
What occurs in secretory lysosome exocytosis?
- An immunolgical synapse is formed at the site the CTL contacts the target cell
- MTOC and secretory lysosomes are polarised to the synapse
- Secretory lysosomes dock and fuse with the plasma membrane
What is FHL-2?
CTL are impaired caused by mutations in perforin, cannot deliver granzymes
What is griscelli syndroms type2?
Mutations in GTPase Rab27a which regulates membrane trafficking. Impaires CTL cytotoxicity.
What is FHL-3?
Mutation in Munc13-4 causing defective cytotoxic function of CTLs, can dock but not fuse.
What is FHL-4?
Caused by mutations in SNARE protein syntaxin 11. Dock but cannot fuse.
