title: Phenotypically distinct B cell development pathways map to the three B cell lineages in the mouse.
abstract: A recent article by Montecino-Rodriguez et al. [Montecino-Rodriguez, E., Leathers, H. & Dorshkind, K. (2006) Nat. Immunol.7, 293-301] has distinguished the early progenitors for B-1 cells, which principally develop in neonates, from early progenitors for B-2 cells, which principally develop in adult bone marrow. Here we introduce syndecan-1 (CD138) and MHC class II (I-A) as markers of early B cell development [Hardy, R. R., Carmack, C. E., Shinton, S. A., Kemp, J. D. & Hayakawa, K. (1991) J. Exp. Med. 173, 1213-1225; Hardy fractions B-D] and show that the expression of these markers distinguishes the predominant B cell development pathway in neonates from the corresponding predominant pathway in adults (both progenitors are present but differently represented in each case). We show that pre-B cells (Hardy fraction D) in the predominant adult pathway express high levels of CD138 and intermediate levels of I-A, whereas the corresponding pre-B cells in the pathway that predominates in neonates do not express either of these markers. As expected, because most of the pre-B cells in adults express CD138, we find that sorted CD138+ adult pre-B cells differentiate to IgM+ B cells in vitro. Sorted CD138- pre-B cells from neonates, the majority subset at this age, also mature to IgM+ cells (without passing through a CD138+ stage). Importantly, our studies here confirm the differential representation of adult and neonatal progenitor populations and further demonstrate that CD138 expression subdivides the adult CD19+, B220-6B2-/low population shown to contain B-1 progenitors in a way consistent with the predominance of B-1b progenitors in adults. Thus, CD138 expression provides a key route to distinguishing early B cell development pathway for what now are clearly three B cell lineages.
authors.affiliation: Department of Genetics, Stanford School of Medicine, Stanford University, Stanford, CA 94305-5318, USA.
authors.forename: James W
authors.initials: JW
authors.lastname: Tung
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Mrazek
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; D000831:Animals, Newborn; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D007075:Immunoglobulin M / Q000276:immunology; D008213:Lymphocyte Activation / Q000235:genetics; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D010641:Phenotype; D011509:Proteoglycans / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D053668:Syndecan-1; D053667:Syndecans
chemical_list: D000949:Histocompatibility Antigens Class II; D007075:Immunoglobulin M; D008562:Membrane Glycoproteins; D011509:Proteoglycans; C508242:Sdc1 protein, mouse; D053668:Syndecan-1; D053667:Syndecans