Adult bone marrow contains precursors for CD5+ B cells

Authors

  • Christene A. Huang,

    1. Department of Pathology, Tufts University School of Medicine and Program in Immunology, Sackler School of Graduate Biomedical Sciences, Boston, USA
    Current affiliation:
    1. Transplantation Biology Research Center, Massachusetts General Hospital East, Building 149 13th Street Boston, MA 02129, USA
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  • Cassis Henry,

    1. Department of Pathology, Tufts University School of Medicine and Program in Immunology, Sackler School of Graduate Biomedical Sciences, Boston, USA
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  • John Iacomini,

    1. Department of Pathology, Tufts University School of Medicine and Program in Immunology, Sackler School of Graduate Biomedical Sciences, Boston, USA
    Current affiliation:
    1. Transplantation Biology Research Center, Massachusetts General Hospital East, Building 149 13th Street Boston, MA 02129, USA
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  • Thereza Imanishi-Kari,

    1. Department of Pathology, Tufts University School of Medicine and Program in Immunology, Sackler School of Graduate Biomedical Sciences, Boston, USA
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  • Henry H. Wortis

    Corresponding author
    1. Department of Pathology, Tufts University School of Medicine and Program in Immunology, Sackler School of Graduate Biomedical Sciences, Boston, USA
    • Department of Pathology, Tufts University School of Medicine, and Program in Immunology, 136 Harrison Avenue, Boston, MA 02111, USA
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Abstract

To determine directly whether B cell precursors of adult origin are capable of generating CD5+ B cells, we reconstituted neonatal C3H.SCID mice with adult C57BL/6 bone marrow and analyzed splenic B cells 10 months later. Surface staining and flow cytometry revealed that the B cells were of donor origin and that 30% were CD5+. This confirms that in vivo generated CD5+ B cells can be adult derived. After anti-IgM (but not lipopolysaccharide) stimulation in vitro, virtually all of the B cells from the bone marrow-reconstituted mice expressed surface CD5. Sequence analysis of expressed VHDJH genes from the CD5+ B cells present after anti-IgM stimulation revealed a high frequency of N nucleotide addition in CDR3 regions. The presence of N nucleotides indicates that these sequences were derived from CD5+ B cells of adult origin rather than from long-lived fetal precursor B cells present in either the adult bone marrow at the time of transfer or adult spleen. These experiments demonstrate conclusively that adult bone marrow contains precursors for CD5+ B cells and that unlike fetal liver-derived precursors these express terminal deoxynucleotidyl transferase.

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