title: Lineage specification and plasticity in CD19- early B cell precursors.
abstract: We describe here three CD19- B cell precursor populations in mouse bone marrow identified using 12-color flow cytometry. Cell transfer experiments indicate lineage potentials consistent with multilineage progenitor (MLP), common lymphoid progenitor (CLP), and B lineage-restricted pre-pro-B (Fr. A), respectively. However, single cell in vitro assays reveal lineage plasticity: lymphoid/myeloid lineage potential for CLP and B/T lineage potential for Fr. A. Despite myeloid potential, recombination activating gene 2 reporter activation is first detected at low levels in most MLP cells, with 95% of CLPs showing 10-fold increased levels. Furthermore, single cell analysis shows that half of CLP and 90% of Fr. A cells contain heavy chain DJ rearrangements. These data, together with expression profiles of lineage-specific genes, demonstrate progressive acquisition of B lineage potential and support an asynchronous view of early B cell development, in which B lineage specification initiates in the MLP/CLP stage, whereas myeloid potential is not lost until the pre-pro-B (Fr. A) stage, and B/T lymphoid plasticity persists until the CD19+ pro-B stage. Thus, MLP, CLP, and Fr. A represent progressively B lineage-specified stages in development, before the CD19+ B lineage-committed pro-B stage.
authors.affiliation: Division of Basic Sciences, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
authors.forename: Lynn L
authors.initials: LL
authors.lastname: Rumfelt
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Rowley
authors.forename: Susan A
authors.initials: SA
authors.lastname: Shinton
authors.forename: Richard R
authors.initials: RR
authors.lastname: Hardy
mesh_terms: D000818:Animals; D018941:Antigens, CD19 / Q000235:genetics / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000276:immunology; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics / Q000276:immunology; D015322:Gene Rearrangement, B-Lymphocyte / Q000235:genetics / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology*; D007143:Immunoglobulin Heavy Chains; D038041:Lymphopoiesis / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008813:Mice, Inbred ICR
chemical_list: D018941:Antigens, CD19; D004268:DNA-Binding Proteins; D007143:Immunoglobulin Heavy Chains; C499308:Rag2 protein, mouse