Adoptive transfer of fluorescence‐labeled cells shows that resident peritonealmacrophages are able to migrate into specialized lymphoid organs and inflammatory sites in the mouse

Abstract

We have examined the migration of murine macrophages from the vascular compartment tonormal and inflammatory tissues by the adoptive transfer of resident peritoneal macrophages (RPMΦ) fluorescently labeled with the hydrophobic dye 1,1′‐dioctadecyl3,3,3′,3′‐tetramethylindocarbocyanine perchlorate (DiI). After initial labeling of the plasma membrane of RPMΦ, the dye accumulated stably in intracellular vesicles of low density (Q = 1.042—1.045 kg/l) and cells remained viable in culture for 4 weeks. Like the normal monocyte, DiI‐RPMΦ, but not exudate‐derived or fixed cells, migrated to peritoneal exudates, following i.v. adoptive transfer, by a mechanism inhibitable by an antibody to the type 3 complement receptor. In the absence of an inflammatory stimulus there was no migration to the peritoneal cavity, and DiI‐RPMΦ, accumulated within 4 h in the red pulp and marginal zone of the spleen. By day 6 these cells still formed a tight ring of fluorescence in the marginal zonealone, outside the marginal metallophil cells. DiI‐RPMΦ injected into the peritoneal cavity migrated to the parathymic lymph nodes where they were found in the subcapsular sinus and in the medullary cords, whereas very few fluorescent cells could be found in the T cell areas. The migration of RPMΦ to lymphoid organs required viable cells but, unlike the recruitment of cells to peritoneal exudates, was not inhibitable by antibodies to CR3. We conclude that the RPMΦ is a useful surrogate for the analysis of constitutive and induced monocyte migration to secondary lymphoid and inflammatory sites, respectively.