title: Ontogenic development of macrophage subpopulations and Ia-positive dendritic cells in fetal and neonatal rat spleen.
abstract: Development, differentiation, and distribution of macrophage subpopulations and Ia+ dendritic cells in the fetal and neonatal rat spleen were investigated by means of double immunohistochemical staining and immunoelectron microscopy. To characterize these cell populations, a panel of anti-rat macrophage monoclonal antibodies (RM-1, ED2, ED3, TRPM-3, Ki-M2R) and an anti-rat Ia antibody (OX6) were used. In the fetal rat spleen, macrophages were first detected by RM-1 at fetal day 15. ED2+ and/or Ki-M2R+ macrophages appeared at fetal day 16. TRPM-3+ and/or ED3+ macrophages appeared a day later. During the fetal and neonatal development, ED2+ and TRPM-3+ macrophages differentiated independently, maturing into red pulp macrophages and marginal metallophilic and marginal zone macrophages respectively. Intimate topographical relations were observed between ED2+ macrophages and hematopoietic cells and between TRPM-3+ macrophages and marginal zone lymphocytes. Ia+ cells were first observed around arterioles at fetal day 15. In the fetal and neonatal period, the number of Ia+ cells gradually increased, their shape became dendritic, and they matured into interdigitating cells in the inner periarteriolar lymphatic sheath. In ontogeny, Ia+ dendritic cells were not stained with ED2 or TRPM-3. These results suggest that ED2+ macrophages, TRPM-3+ macrophages, and Ia+ dendritic cells are distinct cell lines that pursue independent developmental process in spleen ontogeny.
authors.affiliation: Second Department of Pathology, Kumamoto University School of Medicine, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Takeya
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
mesh_terms: D000367:Age Factors; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis*; D000954:Antigens, Surface / Q000032:analysis; D002462:Cell Membrane / Q000276:immunology; D003713:Dendritic Cells / Q000166:cytology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D008264:Macrophages / Q000166:cytology*; D051381:Rats; D017208:Rats, Wistar; D013154:Spleen / Q000166:cytology* / Q000196:embryology
chemical_list: D000911:Antibodies, Monoclonal; D015214:Antigens, Differentiation, Myelomonocytic; D000954:Antigens, Surface; D000949:Histocompatibility Antigens Class II