Transcriptomics identify CD9 as a marker of murine IL10-competent regulatory B cells

• Published in: Cell reports (Cambridge) 2015-10, Vol.13 (6), p.1110-1117
• Main Authors: Sun, Jianbo, Wang, Jiguang, Pefanis, Evangelos, Chao, Jaime, Rothschild, Gerson, Tachibana, Isao, Chen, Jun Kui, Ivanov, Ivaylo I., Rabadan, Raul, Takeda, Yoshito, Basu, Uttiya
• Format: Article
• Language: English
• ISSN: 2211-1247
• DOI: 10.1016/j.celrep.2015.09.070

Regulatory B cells (Breg) have immune suppressive functions in various autoimmune/inflammation models and diseases, and are found enriched in diverse B-cell subsets. The lack of a unique marker or set of markers efficiently identifying Breg cells impedes detailed investigation into their origin, development, and immunological roles. Here, we perform transcriptome analysis of IL10-expressing B cells to identify key regulators for Breg biogenesis and function and identify CD9, a tetraspanin-family transmembrane protein, as a key surface marker for most mouse IL10 + B cells and their progenitors. CD9 plays a role in the suppressive function of IL10 + B cells in ex-vivo T cell proliferation assays through a mechanism that is dependent upon B/T cell interactions. CD9 + B cells also demonstrate inhibition of Th1 mediated contact hypersensitivity in an in vivo model system. Taken together, our findings implicate CD9 in the immunosuppressive activity of regulatory B cells.