title: Identification of a B-1 B cell-specified progenitor.
abstract: The B-1 subpopulation of B lymphocytes differs phenotypically and functionally from conventional B-2 B cells. B-1 B cells are proposed to derive from a distinct progenitor, but such a population has not been isolated. Here we identify and characterize a B-1 B cell progenitor whose numbers peaked in fetal bone marrow but were less abundant in postnatal bone marrow. These Lin(-)CD45R(lo-neg)CD19(+) cells responded to thymic stromal lymphopoietin and 'preferentially' reconstituted functional sIgM(hi)CD11b(+)CD5(lo-neg) B-1 B cells, but not sIgM(+)CD11b(-) B-2 B cells, in vivo. These data indicate that the CD45R(lo-neg)CD19(+) population includes B-1 B cell-specified progenitors and support models proposing distinct developmental pathways for B-1 B cells.
authors.affiliation: Department of Pathology and Laboratory Medicine and the Hematopoietic Malignancies Program, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA.
authors.forename: Encarnacion
authors.initials: E
authors.lastname: Montecino-Rodriguez
authors.forename: Hyosuk
authors.initials: H
authors.lastname: Leathers
authors.forename: Kenneth
authors.initials: K
authors.lastname: Dorshkind
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology / Q000378:metabolism; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D019070:Cell Lineage / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology*; D007150:Immunohistochemistry; D016131:Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010641:Phenotype; D016133:Polymerase Chain Reaction
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte