title: Characterization of marginal zone B cell precursors.
abstract: Selection of recently formed B cells into the follicular or marginal zone (MZ) compartments is proposed to occur by way of proliferative intermediates expressing high levels of CD21/35 and CD23. However, we show that CD21/35(high) CD23(+) splenocytes are not enriched for proliferative cells, and do not contribute substantially to the generation of follicular B cells. Instead, ontogenic relationships, steady-state labeling kinetics, and adoptive transfer experiments suggest that CD21/35(high) CD23(+) splenocytes serve primarily as precursors for MZ B cells, although their developmental potential seems to be broader and is influenced by environmental cues that are associated with lymphopenia. Furthermore, CD21/35(high) CD23(+) splenocytes share several key functional characteristics with MZ B cells, including their capacity to trap T-independent antigen and a heightened proliferative response to LPS. These observations challenge previous models of peripheral B cell maturation, and suggest that MZ B cells develop by way of CD21/35(high) CD23(+) intermediates.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadephia, 19104, USA.
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Srivastava
authors.forename: William J
authors.initials: WJ
authors.lastname: Quinn
authors.forename: Kristin
authors.initials: K
authors.lastname: Hazard
authors.forename: Jan
authors.initials: J
authors.lastname: Erikson
authors.forename: David
authors.initials: D
authors.lastname: Allman
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D001973:Bromodeoxyuridine / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011951:Receptors, Complement / Q000378:metabolism; D017463:Receptors, Complement 3b / Q000378:metabolism; D017464:Receptors, Complement 3d / Q000378:metabolism; D017455:Receptors, IgE / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism / Q000502:physiology*
chemical_list: D008562:Membrane Glycoproteins; D011951:Receptors, Complement; D017463:Receptors, Complement 3b; D017464:Receptors, Complement 3d; D017455:Receptors, IgE; C032402:complement 1q receptor; D001973:Bromodeoxyuridine