Participate in the phagocytic process.

Help process antigens as part of the immune response.

They may become activated during cytokine storms and secrete excessive amounts of cytokines, ultimately causing severe tissue damage and lead to organ failure.

May be fixed or can wander.

Highly variable and function depends on the organ which it resides and any ongoing disease process.

They are tissue resident cells that are often derived from circulating monocytes, and do not divide.

Macrophages are phagocytes in innate immune responses

Fixed macrophages are present in the bone marrow, spleen, lymph nodes, and organs involving endothelium of capillaries.

Pulmonary alveolar macrophages function as a defense against inhaled foreign particles and bacteria.

Lung macrophages important to lung function.

Lung macrophages are present in alveoli and in the airway wall and lumen.

Precursor of monocytes.

In the presence of tissue damage and inflammation substances are released that attract macrophages.

Activated macrophages are eliminate pathogens in both innate and adaptive immune responses, and are also important in tissue homeostasis, through the clearance of senescent cells, and in remodeling and repair of tissue after inflammation. 

Macrophages have a variety of names: including histiocytes in the loose connective tissue, Kupffer cells in the sinusoids of the liver, osteoclasts in bone, and microglial cells in the central nervous system.

These cells along with reticular cells of the spleen, thymus and lymphoid tissues are referred to as mononuclear phagocytes.

Cells of the macrophage system of formed from the progenitor cells in the bone marrow.

A monocyte is influenced by hematopoietic growth factors to transform into a macrophage in the tissues.

Monocytes at the tumor site are induced to differentiate with macrophages into tumor associated macrophages, acquiring pro tumor functions including cancer growth, angiogenesis, dissemination, matrix remodeling, and suppression of adaptive immune response.

Tumor associated macrophages express CD68 in CD163 markers in many tumor types and promote tumorigenesis and cancer progression.

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