title: The identification and developmental requirements of colonic CD169⁺ macrophages.
abstract: CD169-positive macrophages in the marginal zone of the spleen and subcapsular sinus of lymph nodes play an important role as gatekeepers, strategically located to capture pathogens. Here we identified a population of CD169-positive macrophages in the colon and investigated which factors influenced their development. Murine colonic CD115+ F4/80(lo) CD11c(lo) macrophages expressing CD169 were present in the lamina propria, mainly surrounding the crypts. In spite of the high levels of bacterial flora in the colon and the importance of Toll-like receptor signalling in mucosal homeostasis, the presence of CD169+ macrophages was not affected in mice that were deficient in MyD88-mediated Toll-like receptor signalling and in mice in which the bacterial flora was eradicated. Whereas the development of splenic CD169+ macrophages was dependent on lymphotoxin α, colonic CD169+ macrophages were present in normal numbers in lymphotoxin α-deficient mice. In contrast, reduced numbers of CD169+ macrophages were found in the colon of mice deficient in vitamin A, whereas CD169+ macrophages in the spleen were unaffected. In conclusion, we identified a new macrophage subset in the lamina propria of the colon characterized by the expression of CD169. Its differentiation, unlike CD169+ macrophages in lymphoid organs, is independent of lymphotoxin α signalling, but requires vitamin A.
authors.forename: Ida H
authors.initials: IH
authors.lastname: Hiemstra
authors.forename: Marieke R
authors.initials: MR
authors.lastname: Beijer
authors.forename: Henrike
authors.initials: H
authors.lastname: Veninga
authors.forename: Kim
authors.initials: K
authors.lastname: Vrijland
authors.forename: Ellen G F
authors.initials: EG
authors.lastname: Borg
authors.forename: Brenda J
authors.initials: BJ
authors.lastname: Olivier
authors.forename: Reina E
authors.initials: RE
authors.lastname: Mebius
authors.forename: Georg
authors.initials: G
authors.lastname: Kraal
authors.forename: Joke M M
authors.initials: JM
authors.lastname: den Haan
mesh_terms: D000818:Animals; D003106:Colon / Q000166:cytology* / Q000276:immunology* / Q000382:microbiology; D005260:Female; D008233:Lymphotoxin-alpha; D008264:Macrophages / Q000166:cytology* / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009092:Mucous Membrane / Q000166:cytology / Q000276:immunology; D038042:Myelopoiesis; D063267:Sialic Acid Binding Ig-like Lectin 1 / Q000276:immunology*; D014801:Vitamin A / Q000378:metabolism
chemical_list: D008233:Lymphotoxin-alpha; D063267:Sialic Acid Binding Ig-like Lectin 1; D014801:Vitamin A