A Population of CD19highCD45R /lowCD21low B Lymphocytes Poised for Spontaneous Secretion of IgG and IgA Antibodies

• Published in: The Journal of immunology (1950) 2007-10, Vol.179 (8), p.5326-5334
• Main Authors: de Andres, Belen, Cortegano, Isabel, Serrano, Natalia, del Rio, Borja, Martin, Paloma, Gonzalo, Pilar, Marcos, Miguel A. R, Gaspar, Maria Luisa
• Format: Article
• Language: English
• Subjects: Animals; Antigens, CD19 - biosynthesis; B-Lymphocyte Subsets - immunology; B-Lymphocyte Subsets - metabolism; Bone Marrow Cells - immunology; Bone Marrow Cells - metabolism; Cell Differentiation - immunology; Cell Movement - immunology; Cells, Cultured; Cellular Senescence - immunology; Fetus; Hematopoietic Stem Cells - immunology; Hematopoietic Stem Cells - metabolism; Immunoglobulin A - biosynthesis; Immunoglobulin G - biosynthesis; Leukocyte Common Antigens - metabolism; Liver - embryology; Liver - immunology; Liver - metabolism; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Knockout; Multipotent Stem Cells - immunology; Multipotent Stem Cells - metabolism; Plasma Cells - immunology; Plasma Cells - metabolism; Receptors, Complement 3d - metabolism; Spleen - cytology; Spleen - immunology; Spleen - metabolism
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.179.8.5326

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.