PD-L2 expression extends beyond dendritic cells/macrophages to B1 cells enriched for VH11/VH12 and phosphatidylcholine binding

Authors

  • Xuemei Zhong,

    1. Department of Medicine, Boston University Medical Center, Boston, MA, USA
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  • Joseph R. Tumang,

    1. Center for Oncology and Cell Biology, The Feinstein Institute for Medical Research, Manhasset, NY, USA
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  • Wenda Gao,

    1. Transplant Research Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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  • Chunyan Bai,

    1. Department of Medicine, Boston University Medical Center, Boston, MA, USA
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  • Thomas L. Rothstein Dr.

    Corresponding author
    1. Department of Medicine, Boston University Medical Center, Boston, MA, USA
    2. Center for Oncology and Cell Biology, The Feinstein Institute for Medical Research, Manhasset, NY, USA
    • Center for Oncology and Cell Biology, The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, New York 11030, USA, Fax: +1-516-562-2533
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Abstract

B1 B cells are the major source of natural antibody that is essential for innate immunity. The B1 repertoire is skewed toward production of phosphatidylcholine (PtC)-binding VH11 and VH12 immunoglobulin that plays a key role in immune defense against bacterial infection. Programmed death-ligand 2 (PD-L2) is a ligand for the immunosuppressive receptor programmed death-1 (PD-1). It has been reported that expression of PD-L2 is restricted to dendritic cells and macrophages in mice. Here we show that 50–70% of resting peritoneal B1 cells express PD-L2, which is not present or inducible on conventional B2 B cells or PD-L2 B1 cells. Although PD-L2+ and PD-L2 B1 cells are similar in proliferative responses and spontaneous immunoglobulin secretion, PD-L2+ B1 cells are highly enriched for expression of VH11 and VH12 genes and encompass the bulk of PtC-binding B1 cells. These findings extend the range of known PD-L2 expression to B cells and show that B1 cells identified by this marker express a specific repertoire associated with anti-bacterial immunity.

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