title: A subfraction of B220(+) cells in murine bone marrow and spleen does not belong to the B cell lineage but has dendritic cell characteristics.
abstract: Although CD45R/B220 is commonly used as a pan-B cell marker in the mouse, not all B220(+) cells belong to the B cell lineage. Here we report the characterization of a subpopulation of B220(+)CD19(-) cells in murine bone marrow, which failed to express markers that are present in early CD19(--) B cell precursors. Instead, these cells expressed low levels of MHC class II and CD11c, which are typically found on dendritic cells (DC). Moreover, these B220(+)CD19(-)CD11c(+) cells expressed Gr-1, indicating that they are related to the recently identified murine plasmacytoid DC or their progenitors. Therefore, we evaluated surface marker expression of the B220(+)CD19(-)CD11c(+) cells in lymphoid tissues of C57BL/6 mice, recombinase activating gene-1 deficient mice, lacking mature B and T lymphocytes, and mice with a targeted disruption of the Ig H chain mu membrane exon (mu MT), lacking mature B lymphocytes. When comparing bone marrow and spleen, we found that the surface profiles of B220(+)CD19(-)CD11c(+) cells were remarkably similar, indicating that they are in a comparable maturation or activation stage in the two lymphoid compartments. In addition, the almost complete absence of peripheral B220(+) B-lineage cells in mu MT mice allowed the anatomical localization of the B220(+)CD19(-)CD11c(+) cells to the red pulp and the T cell areas in the spleen. Taken together, our findings indicate that the mouse bone marrow contains a recirculating population of B220(+)CD19(-) CD11c(+) plasmacytoid DC, the development of which is largely independent of the presence of mature T and B cells.
authors.affiliation: Department of Immunology, Faculty of Medicine, Erasmus University Rotterdam, Rotterdam, The Netherlands.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Nikolic
authors.forename: Gemma M
authors.initials: GM
authors.lastname: Dingjan
authors.forename: Pieter J M
authors.initials: PJ
authors.lastname: Leenen
authors.forename: Rudolf W
authors.initials: RW
authors.lastname: Hendriks
mesh_terms: D000818:Animals; D018941:Antigens, CD19 / Q000032:analysis; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis*; D016175:B-Lymphocyte Subsets / Q000737:chemistry / Q000145:classification; D001854:Bone Marrow Cells / Q000737:chemistry / Q000145:classification / Q000166:cytology*; D002454:Cell Differentiation; D019070:Cell Lineage; D003713:Dendritic Cells / Q000737:chemistry / Q000166:cytology*; D005434:Flow Cytometry; D016654:Genes, RAG-1; D018398:Homeodomain Proteins / Q000502:physiology; D016130:Immunophenotyping; D016167:Integrin alphaXbeta2 / Q000032:analysis; D007694:Killer Cells, Natural / Q000737:chemistry / Q000145:classification / Q000276:immunology; D017493:Leukocyte Common Antigens / Q000032:analysis*; D016131:Lymphocyte Subsets / Q000737:chemistry / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009928:Organ Specificity; D013154:Spleen / Q000166:cytology*
chemical_list: D018941:Antigens, CD19; D000944:Antigens, Differentiation, B-Lymphocyte; D018398:Homeodomain Proteins; D016167:Integrin alphaXbeta2; C064658:RAG-1 protein; D017493:Leukocyte Common Antigens