title: Distinct progenitors for B-1 and B-2 cells are present in adult mouse spleen.
abstract: Recent studies by Dorshkind, Yoder, and colleagues show that embryonic (E9) B-cell progenitors located in the yolk sac and intraembryonic hemogenic endothelium before the initiation of circulation give rise to B-1 and marginal zone B cells but do not give rise to B-2 cells. In studies here, we confirm and extend these findings by showing that distinct progenitors for B-1 and B-2 cells are present in the adult spleen. Furthermore, we show that the splenic B-cell progenitor population (lin(-)CD19(+)/B220(lo/-)/CD43(-)) that gives rise to B-1 cells is likely to be heterogeneous because, in some recipients, it also gives rise to B cells expressing the marginal zone phenotype (B220(hi)IgM(hi)IgD(lo)CD21(hi)) and to some (CD19(-)CD5(hi)) T cells. In addition to the well-known function differences between B-1 and B-2, our studies demonstrate that substantial developmental differences separate these B-cell lineages. Thus, consistent with the known dependence of B-2 development on IL-7, all B-2 progenitors express IL-7R. However, >30% of the B-1 progenitors do not express this marker, enabling the known IL-7 independent development of B-1 cells in IL-7(-/-) mice. In addition, marker expression on cells in the early stages of the B-2 development pathway (CD19(-)/c-Kit(lo/-)/Sca-1(lo/-)) in adult bone marrow distinguish it from the early stages of B-1 development (CD19(hi)/c-Kit(+)/Sca-1(+)), which occur constitutively in neonates. In adults, in vivo inflammatory stimulation (LPS) triggers B-1 progenitors in spleen to expand and initiate development along this B-1 developmental pathway.
authors.affiliation: Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA. eliverg@stanford.edu
authors.forename: Eliver Eid Bou
authors.initials: EE
authors.lastname: Ghosn
authors.forename: Patricia
authors.initials: P
authors.lastname: Sadate-Ngatchou
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Leonard A
authors.initials: LA
authors.lastname: Herzenberg
authors.forename: Leonore A
authors.initials: LA
authors.lastname: Herzenberg
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D018941:Antigens, CD19 / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology*; D049109:Cell Proliferation; D005434:Flow Cytometry; D006410:Hematopoiesis / Q000276:immunology / Q000502:physiology*; D017493:Leukocyte Common Antigens / Q000378:metabolism; D051917:Leukosialin / Q000378:metabolism; D008070:Lipopolysaccharides; D038041:Lymphopoiesis / Q000276:immunology / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D054448:Precursor Cells, B-Lymphoid / Q000166:cytology* / Q000276:immunology; D020395:Receptors, Interleukin-7 / Q000235:genetics / Q000378:metabolism*; D013154:Spleen / Q000166:cytology* / Q000502:physiology
chemical_list: D000911:Antibodies, Monoclonal; D018941:Antigens, CD19; D051917:Leukosialin; D008070:Lipopolysaccharides; D020395:Receptors, Interleukin-7; D017493:Leukocyte Common Antigens