title: A feeder-free differentiation system identifies autonomously proliferating B cell precursors in human bone marrow.
abstract: The peripheral B cell compartment is maintained by homeostatic proliferation and through replenishment by bone marrow precursors. Because hematopoietic stem cells cycle at a slow rate, replenishment must involve replication of precursor B cells. To study proliferation of early human B cell progenitors, we established a feeder cell-free in vitro system allowing the development of B cells from CD34(+) hematopoietic stem cells up to the stage of immature IgM(+) B cells. We found that pro-B and pre-B cells generated in vitro can proliferate autonomously and persist up to 7 wk in culture in the absence of signals induced by exogenously added cytokines. Nevertheless, addition of IL-7 enhanced pre-B cell expansion and inhibited maturation into IgM(+) B cells. The B cell precursor subsets replicating in vitro were highly similar to the bone marrow B cell precursors cycling in vivo. The autonomous proliferation of B cell precursor subsets in vitro and their long-term persistence implies that proliferation during pro-B and pre-B cell stages plays an important role in the homeostasis of the peripheral B cell compartment. Our in vitro culture can be used to study defects in B cell development or in reconstitution of the B cell pool after depletion and chemotherapy.
authors.affiliation: Center for Chronic Immunodeficiency, University Medical Center Freiburg, 79108 Freiburg, Germany;
authors.forename: Helene
authors.initials: H
authors.lastname: Kraus
authors.forename: Sandra
authors.initials: S
authors.lastname: Kaiser
authors.forename: Konrad
authors.initials: K
authors.lastname: Aumann
authors.forename: Peter
authors.initials: P
authors.lastname: Bönelt
authors.forename: Ulrich
authors.initials: U
authors.lastname: Salzer
authors.forename: Dietmar
authors.initials: D
authors.lastname: Vestweber
authors.forename: Miriam
authors.initials: M
authors.lastname: Erlacher
authors.forename: Mirjam
authors.initials: M
authors.lastname: Kunze
authors.forename: Meike
authors.initials: M
authors.lastname: Burger
authors.forename: Kathrin
authors.initials: K
authors.lastname: Pieper
authors.forename: Heiko
authors.initials: H
authors.lastname: Sic
authors.forename: Antonius
authors.initials: A
authors.lastname: Rolink
authors.forename: Hermann
authors.initials: H
authors.lastname: Eibel
authors.forename: Marta
authors.initials: M
authors.lastname: Rizzi
mesh_terms: D000328:Adult; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology*; D001853:Bone Marrow; D018929:Cell Culture Techniques / Q000379:methods*; D002455:Cell Division; D019070:Cell Lineage; D002478:Cells, Cultured; D018920:Coculture Techniques; D004268:DNA-Binding Proteins / Q000172:deficiency; D005312:Fetal Blood / Q000166:cytology; D006085:Graft Survival; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D064593:Heterografts; D006706:Homeostasis; D006801:Humans; D007075:Immunoglobulin M / Q000096:biosynthesis; D016130:Immunophenotyping; D015851:Interleukin-7 / Q000494:pharmacology; D038041:Lymphopoiesis / Q000187:drug effects; D051379:Mice; D011828:Radiation Chimera; D015375:Receptors, Interleukin-2 / Q000172:deficiency; D013997:Time Factors; D055815:Young Adult
chemical_list: D004268:DNA-Binding Proteins; D007075:Immunoglobulin M; D015851:Interleukin-7; C499308:Rag2 protein, mouse; D015375:Receptors, Interleukin-2