Mononuclear phagocyte system

Mononuclear phagocyte system (MPS), also known as the reticuloendothelial system (RES), is a part of the immune system that consists of phagocytic cells located in reticular connective tissue. The cells are primarily monocytes and macrophages, and they accumulate in lymph nodes and the spleen. The Kupffer cells of the liver and tissue histiocytes are also part of the MPS.

Function

The primary function of the MPS is the phagocytosis, or engulfing and then digesting, of cellular debris and pathogens. Additionally, the MPS is responsible for the development and release of monocytes and macrophages, important immune cells that are capable of destroying pathogens through phagocytosis.

Components

The MPS is composed of monocytes and macrophages. Monocytes are produced in the bone marrow and released into the blood. They have a short half-life in the blood (about 1 to 3 days), after which they migrate to tissues and develop into different types of macrophages.

Macrophages are found in all tissues and are the primary cells of the MPS. They are responsible for phagocytosing pathogens and dead cells, and they also help to stimulate the immune response by presenting antigens to T cells and releasing cytokines.

Clinical significance

The MPS plays a crucial role in host defense against infections. Defects in the MPS can lead to increased susceptibility to infections. In addition, the MPS is involved in the pathogenesis of certain diseases such as atherosclerosis, rheumatoid arthritis, and cancer.

See also

• Phagocyte
• Macrophage
• Monocyte
• Immune system