title: A population of CD19highCD45R-/lowCD21low B lymphocytes poised for spontaneous secretion of IgG and IgA antibodies.
abstract: Ab responses to selected Ags are produced by discrete B cell populations whose presence and functional relevance vary along the ontogeny. The earliest B lineage-restricted precursors in gestational day 11 mouse embryos display the CD19(+)CD45R/B220(-) phenotype. Phenotypically identical cells persist throughout gestation and in postnatal life, in parallel to the later-arising, CD19(+)CD45R(+) B cells. Very early after birth, the CD19(+)CD45R(-) B cell subset included high frequencies of spontaneously Ig-secreting cells. In the adult spleen, a small subset of CD19(high)CD45R(-/low)IgM(+/-)IgD(-)CD21/Cr2(-/low) cells, which was detected in perifollicular areas, displayed genetic and phenotypical traits of highly differentiated B cells, and was enriched in IgG- and IgA-secreting plasma cells. In vitro differentiation and in vivo adoptive transfer experiments of multipotent hemopoietic progenitors revealed that these CD19(high)CD45R(-/low) B cells were preferentially regenerated by embryo-, but not by adult bone marrow-, derived progenitors, except when the latter were inoculated into newborn mice. Both the early ontogenical emergence and the natural production of serum Igs, are shared features of this CD19(high)CD45R(-/low) B cell population with innate-like B lymphocytes such as B1 and marginal zone B cells, and suggest that the new population might be related to that category.
authors.affiliation: Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain. bdandres@isciii.es
authors.forename: Belén
authors.initials: B
authors.lastname: de Andrés
authors.forename: Isabel
authors.initials: I
authors.lastname: Cortegano
authors.forename: Natalia
authors.initials: N
authors.lastname: Serrano
authors.forename: Borja
authors.initials: B
authors.lastname: del Rio
authors.forename: Paloma
authors.initials: P
authors.lastname: Martín
authors.forename: Pilar
authors.initials: P
authors.lastname: Gonzalo
authors.forename: Miguel A R
authors.initials: MA
authors.lastname: Marcos
authors.forename: María Luisa
authors.initials: ML
authors.lastname: Gaspar
mesh_terms: D000818:Animals; D018941:Antigens, CD19 / Q000096:biosynthesis*; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology; D002465:Cell Movement / Q000276:immunology; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000276:immunology; D005333:Fetus; D006412:Hematopoietic Stem Cells / Q000276:immunology / Q000378:metabolism; D007070:Immunoglobulin A / Q000096:biosynthesis*; D007074:Immunoglobulin G / Q000096:biosynthesis*; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008099:Liver / Q000196:embryology / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D018345:Mice, Knockout; D039902:Multipotent Stem Cells / Q000276:immunology / Q000378:metabolism; D010950:Plasma Cells / Q000276:immunology / Q000378:metabolism; D017464:Receptors, Complement 3d / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism
chemical_list: D018941:Antigens, CD19; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D017464:Receptors, Complement 3d; D017493:Leukocyte Common Antigens