Editing Macrophage (section)

== Structure ==
=== Types ===
{{Main|Mononuclear phagocyte system}}
{{Redirect|Macrophage activation|the signal|Macrophage-activating factor|the disease syndrome|Macrophage activation syndrome}}
[[File:Giemsa Stain Macrophage Illustration.png|thumb|250px|Drawing of a macrophage when fixed and stained by [[giemsa stain|giemsa dye]]]]

A majority of macrophages are stationed at strategic points where microbial invasion or accumulation of foreign particles is likely to occur. These cells together as a group are known as the [[mononuclear phagocyte system]] and were previously known as the reticuloendothelial system. Each type of macrophage, determined by its location, has a specific name:

{| class="wikitable"
|-
| '''Cell Name''' || '''Anatomical Location'''
|-
| [[Adipose tissue macrophages]] || [[Adipose tissue]] (fat)
|-
| [[Monocyte]]s || [[Bone marrow]] / [[blood]]
|-
| [[Kupffer cell]]s || [[Liver]]
|-
| [[Medulla of lymph node|Sinus histiocytes]] || [[Lymph node]]s
|-
| [[Alveolar macrophage]]s (dust cells) || [[Pulmonary alveolus|Pulmonary alveoli]]
|-
| [[#Tissue macrophages|Tissue macrophage]]s (histiocytes) leading to [[giant cell]]s || [[Connective tissue]]
|-
| [[Microglia]] || [[Central nervous system]]
|-
| [[Hofbauer cell]]s  || [[Placenta]]
|-
| [[Intraglomerular mesangial cell]]s<ref>{{cite book | vauthors = Lote CJ |title= Principles of Renal Physiology, 5th edition|publisher=Springer |page=37}}</ref> || [[Kidney]]
|-
| [[Osteoclast]]s <ref>{{cite journal | vauthors = Shirazi S, Ravindran S, Cooper LF | title = Topography-mediated immunomodulation in osseointegration; Ally or Enemy | journal = Biomaterials | volume = 291 | pages = 121903 | date = December 2022 | pmid = 36410109 | doi = 10.1016/j.biomaterials.2022.121903 | pmc = 10148651 }}</ref>|| [[Bone]]
|-
| [[Langerhans cell]]s || [[Skin]]
|-
| [[Epithelioid cell|Epithelioid]] cells  || [[Granulomas]]
|-
| [[Red pulp|Red pulp macrophage]]s ([[Sinusoid (blood vessel)|sinusoidal]] lining cells) || Red pulp of [[spleen]]
|-
| Peritoneal macrophages || [[Peritoneal cavity]]
|-

|
|-
| perivascular Macrophages<ref name="pmid36450771">{{cite journal | vauthors = Siret C, van Lessen M, Bavais J, Jeong HW, Reddy Samawar SK, Kapupara K, Wang S, Simic M, de Fabritus L, Tchoghandjian A, Fallet M, Huang H, Sarrazin S, Sieweke MH, Stumm R, Sorokin L, Adams RH, Schulte-Merker S, Kiefer F, van de Pavert SA | title = Deciphering the heterogeneity of the Lyve1+ perivascular macrophages in the mouse brain. | journal = Nature Communications | year = 2022 | volume = 13 | issue = 1 | pages = 7366 | pmid = 36450771 | doi = 10.1038/s41467-022-35166-9 | pmc = 9712536 | bibcode = 2022NatCo..13.7366S | doi-access = free }}</ref> || closely associated with blood vessels
|}

Investigations concerning Kupffer cells are hampered because in humans, Kupffer cells are only accessible for immunohistochemical analysis from biopsies or autopsies. From rats and mice, they are difficult to isolate, and after purification, only approximately 5&nbsp;million cells can be obtained from one mouse.

Macrophages can express [[paracrine]] functions within organs that are specific to the function of that organ. In the [[testis]], for example, macrophages have been shown to be able to interact with [[Leydig cells]] by secreting [[25-hydroxycholesterol]], an [[oxysterol]] that can be converted to [[testosterone]] by neighbouring Leydig cells.<ref name="Nes2000">{{cite journal | vauthors = Nes WD, Lukyanenko YO, Jia ZH, Quideau S, Howald WN, Pratum TK, West RR, Hutson JC | title = Identification of the lipophilic factor produced by macrophages that stimulates steroidogenesis | journal = Endocrinology | volume = 141 | issue = 3 | pages = 953–958 | date = March 2000 | pmid = 10698170 | doi = 10.1210/endo.141.3.7350 | doi-access = free }}</ref> Also, testicular macrophages may participate in creating an immune privileged environment in the testis, and in mediating infertility during inflammation of the testis.

Cardiac resident macrophages participate in electrical conduction via [[gap junction]] communication with cardiac [[myocyte]]s.<ref>{{cite journal | vauthors = Hulsmans M, Clauss S, Xiao L, Aguirre AD, King KR, Hanley A, Hucker WJ, Wülfers EM, Seemann G, Courties G, Iwamoto Y, Sun Y, Savol AJ, Sager HB, Lavine KJ, Fishbein GA, Capen DE, Da Silva N, Miquerol L, Wakimoto H, Seidman CE, Seidman JG, Sadreyev RI, Naxerova K, Mitchell RN, Brown D, Libby P, Weissleder R, Swirski FK, Kohl P, Vinegoni C, Milan DJ, Ellinor PT, Nahrendorf M | title = Macrophages Facilitate Electrical Conduction in the Heart | journal = Cell | volume = 169 | issue = 3 | pages = 510–522.e20 | date = April 2017 | pmid = 28431249 | pmc = 5474950 | doi = 10.1016/j.cell.2017.03.050 }}</ref>

Macrophages can be classified on basis of the fundamental function and activation. According to this grouping, there are [[Macrophage polarization#M1 macrophages|classically activated (M1) macrophages]], wound-healing macrophages (also known as [[Macrophage polarization#M2 macrophages|alternatively-activated (M2) macrophages]]), and [[regulatory macrophages]] (Mregs).<ref name="Mosser-2008">{{cite journal | vauthors = Mosser DM, Edwards JP | title = Exploring the full spectrum of macrophage activation | journal = Nature Reviews. Immunology | volume = 8 | issue = 12 | pages = 958–969 | date = December 2008 | pmid = 19029990 | pmc = 2724991 | doi = 10.1038/nri2448 }}</ref>