A phagocyte is a cell that ingests and destroys foreign matter such as microorganisms or debris via a process known as phagocytosis, they can also induce apoptosis of normal and tumor cells, produce cationic proteins, complement components and clotting factors, arachidonic acid metabolites, prostaglandins, leukotrienes, thromboxanes, cytokines, proteases and hydrolases, reactive oxygen and nitrogen intermediates.

These phagocytes are extremely useful as an initial immune system response to infection; neutrophils will be the first type of phagocyte to migrate to sites of injury and fight bacteria by releasing cytotoxic granules and by phagocytosis.

Phagocytes engulf not only pathogens but also debris, dead or dying cells and extracellular matrix. Phagocytosis is an active process in wound healing. After engulfment into a phagosome, a lysosome which is filled with digestive enzymes (proteases and oxygen radicals) will join it to form the phagolysosome to digest phagocytosed material.

In the case of pathogen phagocytosis, professional antigen-presenting cells (i.e.: dendritic cells and macrophage) will translocate to MHC class II small peptide that resulted from the digestion. Helper T helper cells(CD4+) later recognize these antigens presented through MHC class II complemented with a second signal and they will further supplement the cell mediated immune response.

alpha-1-Antitrypsin

• a marker for mononuclear phagocytes in renal biopsies. PMID: 6347490

c-fms

• a member of the Platelet-derived Growth Factor (PDGF) receptor family of receptor tyrosine kinases (RTKs), is the receptor for macrophage colony stimulating factor (CSF-1) that regulates proliferation, differentiation and survival of cells of the mononuclear phagocyte lineage. PMID: 17292918

CD11b/CD18 (beta 2 integrins)

• the mononuclear phagocyte marker. PMID: 16283111, PMID: 9279527
• a phagocyte and NK cell membrane receptor with multiple ligand specificities and functions. PMID: 8485905

CD11c/CD18

• phagocyte-associated integrin alpha X beta 2. PMID: 11170719
• a member of the leukocyte integrin family, is the second phagocyte receptor. PMID: 7535339

CD14

• a phagocyte-expressed pattern recognition receptor that functionally interacts with both TLR2 and TLR4. PMID: 17056568
• monocyte-derived cells with phagocytosis such as erythrophagocytosis, anthracosis, or tingible bodies macrophage lacked CD14 and CD169. PMID: 16360418
• mononuclear phagocyte marker. PMID: 15755524, PMID: 8238257
• The lipopolysaccharide (LPS) receptor complex of mononuclear phagocytes is composed of Toll-like receptor-4 (TLR4), MD-2 and CD14. PMID: 12505201
• involved independently in nonopsonic phagocytosis of different P. aeruginosa strains. PMID: 11262203
• anchored to the mononuclear phagocyte membrane (mCD14) enhances response to LPS. PMID: 9176258

CD36

• phagocytic receptor for bacteria, is a mononuclear phagocyte marker. PMID: 16061696, PMID: 9374033, PMID: 15755524
• CD36 gene transfer can confer "professional" capacity to ingest apoptotic cells upon "amateur" phagocytes. PMID: 7536797

CD64

• a phagocyte receptor, is phagocyte-associated marker. PMID: 10361245

CD68

• a mononuclear phagocyte marker. PMID: 15755524, PMID: 16687312, PMID: 15763343
• a transmembrane glycoprotein expressed in all cells of the mononuclear phagocyte lineage including monocytes and tissue resident macrophages. PMID: 12676954

CD204

• a mononuclear phagocyte marker. PMID: 15755524

c-fms

• related to the receptor for the mononuclear phagocyte growth factor, CSF-1, is a marker for early fetal phagocytes. PMID: 2408759

CR3 (C3 receptor)

• expressed on phagocytic cells, minor subsets of B and T cells, and natural killer (NK) cells. PMID: 8485905

CSF-1

• restricted to cells of the mononuclear phagocytic lineage and is a 165 kd glycoprotein with an associated tyrosine kinase. PMID: 2408759
• expressed on phagocytic cells in the yolk sac and throughout the embryo before the onset of liver hematopoiesis. PMID: 10381505
• On normal cells CSF-1 receptors were restricted in their expression to cells of the mononuclear phagocyte lineage. PMID: 2465043
• known to prime mononuclear phagocytes (MNP) for inflammatory stimuli in vitro. PMID: 9468283
• can act as a circulating regulator of the mononuclear phagocyte system. PMID: 3053899
• mononuclear phagocyte growth factor. PMID: 3010289
• a hemopoietic growth factor that specifically regulates the survival, proliferation, and differentiation of mononuclear phagocytic cells. PMID: 3871440

ED1/ED2

• recognize exclusively cells of the mononuclear phagocyte system (MPS) in the rat. PMID: 8244767

F4/80

• permits identification of early mononuclear phagocyte precursors in the bone marrow. PMID: 6355361

Mac-1

• a rat-anti-mouse phagocyte-specific monoclonal antibody. PMID: 7451976

MARCO

• a mononuclear phagocyte marker. PMID: 15755524

M-CSF

• restricted to the cell populations of the mononuclear phagocyte system. PMID: 1409676
• a homodimeric glycoprotein required for the lineage-specific growth of cells of the mononuclear phagocyte series. PMID: 2852667

MITF

• an Early Phagocyte Marker. PMID: 10381505

MRP8/MRP14

• a marker of phagocyte system activity. PMID: 12594109

Meloperoxidase (MPO)

• a phagocyte activation marker. PMID: 15008386

p150,95 molecule

• a marker of human mononuclear phagocytes: comparison with expression of class II molecules. PMID: 3456894

RFD7

• mature phagocyte marker. PMID: 1893636

S100 proteins

• the phagocyte-specific calcium-binding proteins are pro-inflammatory molecules expressed and secreted by phagocytes, which play a pivotal role within the innate immune system. PMID: 15149869

TAcP (Tartrate-resistant acid phosphatase)

• a differentiation marker for the human mononuclear phagocyte system. PMID: 6677565

TFEC

• most likely acts as a transcriptional repressor in heterodimers with other MiT family members, was identified in cells of the mononuclear phagocyte lineage, coexpressed with all other known MiT subfamily members (Mitf, TFE3, TFEB). PMID: 9973413

TPP-ase

• a histochemical staining for a microglia/phagocyte marker. PMID: 9757622

Other Phagocyte Markers

• Cytochemical markers for mononuclear phagocytes as demonstrated in reactive microglia and globoid cells. PMID: 6774584
• Characterization of mononuclear phagocytes in human CSF using membrane markers. PMID: 1069450