Blocking phagosome-lysosome fusion

Why is phagosome-lysosome fusion important in pathogen destruction?

It is required for pathogen digestion via phagocytosis and for antigen presentation via MHC class II molecules.

How do some pathogens evade destruction after being phagocytosed?

They block the fusion of the phagosome with the lysosome, allowing them to multiply within an endocytic vesicle.

What additional immune process is inhibited when phagosome-lysosome fusion is blocked?

Antigen presentation via MHC class II molecules is blocked because lysosomal digestion is necessary.

How does Mycobacterium tuberculosis prevent phagosome-lysosome fusion?

It targets host proteins involved in membrane trafficking and fusion.

What specific mechanism does M. tuberculosis use to inactivate host proteins involved in phagosome-lysosome fusion?

It uses protein phosphatases to dephosphorylate and inactivate host proteins.

How does M. tuberculosis block acidification within the phagosome?

It prevents the assembly of proton pumps produced by the host cell.