Phagosome

Definition

A phagosome is a vesicle formed around a particle engulfed by a phagocyte via phagocytosis. It eventually fuses with lysosomes to digest the ingested material.

5 Must Know Facts For Your Next Test

1. Phagosomes are crucial for innate immune responses against pathogens.
2. They fuse with lysosomes to form phagolysosomes, where the ingested material is broken down by enzymes.
3. The formation of a phagosome begins with the recognition and binding of a pathogen to a phagocyte.
4. Phagosomes play a role in presenting antigens to T cells, linking innate and adaptive immunity.
5. Defects in phagosome formation or function can lead to chronic granulomatous disease (CGD).

Review Questions

• What is the primary function of a phagosome in the immune system?
• How does the fusion of a phagosome with a lysosome enhance its pathogen-destroying capability?
• Why is the interaction between phagosomes and T cells important for adaptive immunity?

Related terms

Phagocytosis:

The process by which a cell engulfs particles such as bacteria, other microorganisms, aged red blood cells, foreign matter, etc.

Lysosome: An organelle containing digestive enzymes that breaks down waste materials and cellular debris.

Antigen-Presenting Cell (APC): A cell that displays foreign antigens complexed with major histocompatibility complexes on their surfaces.