title: Reduced production of B-1-specified common lymphoid progenitors results in diminished potential of adult marrow to generate B-1 cells.
abstract: B-1 B cells have been proposed to be preferentially generated from fetal progenitors, but this view is challenged by studies concluding that B-1 production is sustained throughout adult life. To address this controversy, we compared the efficiency with which hematopoietic stem cells (HSCs) and common lymphoid progenitors (CLPs) from neonates and adults generated B-1 cells in vivo and developed a clonal in vitro assay to quantify B-1 progenitor production from CLPs. Adult HSCs and CLPs generated fewer B-1 cells in vivo compared with their neonatal counterparts, a finding corroborated by the clonal studies that showed that the CLP compartment includes B-1- and B-2-specified subpopulations and that the former cells decrease in number after birth. Together, these data indicate that B-1 lymphopoiesis is not sustained at constant levels throughout life and define a heretofore unappreciated developmental heterogeneity within the CLP compartment.
authors.affiliation: Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA 90095, USA.
authors.forename: Chad L
authors.initials: CL
authors.lastname: Barber
authors.forename: Encarnacion
authors.initials: E
authors.lastname: Montecino-Rodriguez
authors.forename: Kenneth
authors.initials: K
authors.lastname: Dorshkind
mesh_terms: D000367:Age Factors; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology*; D001853:Bone Marrow / Q000502:physiology*; D002999:Clone Cells; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D007107:Immune System / Q000254:growth & development; D018655:Lymphocyte Count; D054503:Lymphoid Progenitor Cells / Q000166:cytology*; D038041:Lymphopoiesis / Q000276:immunology*; D051379:Mice