Cells of the Immune System: Phagocytes

This lesson covers:

  1. The role of phagocytes in the immune response
  2. The process of phagocytosis

Phagocytes

Phagocytosis is a type of non-specific defence involving a type of cell known as a phagocyte. 

Flowchart showing non-specific and specific defence mechanisms including phagocytosis, cellular response, and humoral response.

Phagocytes are a type of white blood cell that engulf and destroy pathogens (phagocytosis). They are found in the blood and body tissues of many organisms. 


There are two main types of phagocyte: 

  1. Neutrophils - These rapidly engulf and destroy pathogens at the site of infection.
  2. Macrophages - These engulf and digest pathogens but also present the pathogen's antigens on its cell surface to activate other cells in the immune system.

Phagocytosis

The process of phagocytosis is carried out as follows:

Diagram showing the process of phagocytosis with a phagocyte interacting with a pathogen.

The pathogen releases chemicals that attract a phagocyte. 

The diagrams above only show one phagocyte and one pathogen, but in reality many phagocytes and many pathogens interact at the same time.