"eat" invading organisms and include 1) the neutrophil, which is the most common type--it usually attacks bacteria; 2) the monocyte, which is the largest type--it plays several roles in immunity; 3) the macrophage, which patrols for pathogens and removes dead and dying cells; and 4) the mast cell, which helps heal wounds and defends against pathogens.
Another aspect of receptor cooperation is observed when integrin receptors, such as the CR3, increase their affinity for their ligand only after the phagocyte
gets extra stimuli through TLRs , Fc receptors , or CD44 .
Activation of the superoxide-producing phagocyte
NADPH oxidase requires co-operation between the tandem SH3 domains of p47phox in recognition of a polyproline type II helix and an adjacent alpha-helix of p22phox.
Chronic granulomatous disease is a rare inherited disorder characterised by inability of phagocytes
to generate reactive oxygen species needed for intracellular killing of phagocytosed microorganisms.
Milk fat globule epidermal growth factor 8 (MFG-E8), a protein expressed mainly by activated macrophages and immature dendritic cells, is required for the phagocytosis of apoptotic cells as it links externalized phosphatidylserine present on the surface of apoptotic cells with integrins expressed on phagocytes
What can we find in nature to change the course so that phagocytes
can operate as they were intended?
Differentiation of human mononuclear phagocytes
increases their innate response to Mycobacterium tuberculosis infection.
Histocytes and phagocytes
were occasionally found in one patient and clearly seen in seven patients.
Karlsson, "Intracellular generation of superoxide by the phagocyte
NADPH oxidase: how, where, and what for?" Free Radical Biology and Medicine, vol.
Key players are the complement system and professional phagocytes
system and disorders of granulopoiesis and granulocyte function.
Monocytes, macrophages and neutrophils are professional phagocytes
; however other cells can perform phagocytosis so that the cell requires the detection of the foreign particle through membrane receptors.