B-lymphoid cells with attributes of dendritic cells regulate T cells via indoleamine 2,3-dioxygenase |
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| Authors: | Burles A Johnson III David J Kahler Babak Baban Phillip R Chandler Baolin Kang Michiko Shimoda Pandelakis A Koni Jeanene Pihkala Bojan Vilagos Meinrad Busslinger David H Munn Andrew L Mellor |
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| Institution: | aImmunotherapy and Cancer Centers, Departments of;bPathology and;cMedicine, and;dFlow Cytometry Core Facility, Medical College of Georgia, Augusta, GA 30912;;eResearch Institute of Molecular Pathology, A-1030 Vienna, Austria; and;fDepartment of Pediatrics, Medical College of Georgia, Augusta, GA 30912 |
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| Abstract: | A discrete population of splenocytes with attributes of dendritic cells (DCs) and coexpressing the B-cell marker CD19 is uniquely competent to express the T-cell regulatory enzyme indoleamine 2,3-dioxygenase (IDO) in mice treated with TLR9 ligands (CpGs). Here we show that IDO-competent cells express the B-lineage commitment factor Pax5 and surface immunoglobulins. CD19 ablation abrogated IDO-dependent T-cell suppression by DCs, even though cells with phenotypic attributes matching IDO-competent cells developed normally and expressed IDO in response to interferon γ. Consequently, DCs and regulatory T cells (Tregs) did not acquire T-cell regulatory functions after TLR9 ligation, providing an alternative perspective on the known T-cell regulatory defects of CD19-deficient mice. DCs from B-cell–deficient mice expressed IDO and mediated T-cell suppression after TLR9 ligation, indicating that B-cell attributes were not essential for B-lymphoid IDO-competent cells to regulate T cells. Thus, IDO-competent cells constitute a distinctive B-lymphoid cell type with quintessential T-cell regulatory attributes and phenotypic features of both B cells and DCs. |
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| Keywords: | B cells T-cell regulation CD19 |
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