Phagolysosome

In biology, a phagolysosome, or endolysosome, is a cytoplasmic body formed by the fusion of a phagosome with a lysosome in a process that occurs during phagocytosis. Formation of phagolysosomes is essential for the intracellular destruction of microorganisms and pathogens. It takes place when the phagosome's and lysosome's membranes 'collide', at which point the lysosomal contents—including hydrolytic enzymes—are discharged into the phagosome in an explosive manner and digest the particles that the phagosome had ingested. Some products of the digestion are useful materials and are moved into the cytoplasm; others are exported by exocytosis.

Membrane fusion of the phagosome and lysosome is regulated by the Rab5 protein,^[1] a G protein that allows the exchange of material between these two organelles but prevents complete fusion of their membranes.^[1]

When the phagosome and lysosome interact with one another, they form a fully developed phagolysosome. A fully developed phagolysosome consists of digestive and aseptic properties. The purpose of phagolysosomes is to act as a protective barrier. It is a defense line that kills pathogenic bacteria that may have slipped through detection of the other immune system cells. The extracellular space that surrounds the lysosome is very acidic which is important for degradation because most cells cannot handle an acidic environment and will die, with an exception of a few.^[2]