• IMMUNE NETWORK
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• v.10 no.6
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• pp.247-249
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• 2010

Foxp3 is a transcript factor for regulatory T cell development. Interestingly, Foxp3-expressing cells were identified in B cells, especially in CD19(+)CD5(+) B cells, while those were not examined in CD19(+)CD5(-) B cells. Foxp3-expressing CD5(+) B cells in this study were identified in human PBMCs and were found to consist of $8.5{\pm}3.5%$ of CD19(+)CD5(+) B cells. CD19(+)CD5(+)Foxp3(+) B cells showed spontaneous apoptosis. Rare CD19(+)CD5(+) Foxp3(+) regulatory B cell (Breg) population was unveiled in human peripheral blood mononuclear cells and suggested as possible regulatory B cells (Breg) as regulatory T cells (Treg). The immunologic and the clinical relevant of Breg needs to be further investigated.

• BMB Reports
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• v.48 no.1
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• pp.54-59
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• 2015

IL-10-producing B (Breg) cells regulate various immune responses. However, their phenotype remains unclear. CD40 expression was significantly increased in B cells by LPS, and the Breg cells were also enriched in $CD40^{hi}CD5^+$ B cells. Furthermore, CD40 expression on Breg cells was increased by IL-10, CD40 ligand, and B cell-activating factor, suggesting that $CD40^{hi}$ is a common phenotype of Breg cells. LPS-induced CD40 expression was largely suppressed by an anti-IL-10 receptor antibody and in IL-$10^{-/-}CD5^+CD19^+$ B cells. The autocrine effect of IL-10 on the CD40 expression was largely suppressed by an inhibitor of JAK/STAT3. In vivo, the LPS treatment increased the population of $CD40^{hi}CD5^+$ Breg cells in mice. However, the population of $CD40^{hi}CD5^+$ B cells was minimal in IL-$10^{-/-}$ mice by LPS. Altogether, our findings show that Breg cells are largely enriched in $CD40^{hi}CD5^+$ B cells and the autocrine effect of IL-10 is critical to the formation of $CD40^{hi}CD5^+$ Breg cells.

• BMB Reports
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• v.54 no.10
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• pp.534-539
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• 2021

IL-10⁺ regulatory B (Breg) cells play a vital role in regulating the immune responses in experimental autoimmune encephalomyelitis, colitis, and contact hypersensitivity (CHS). Several stimulants such as lipopolysaccharide (LPS), CD40 ligand, and IL-21 spur the activation and maturation of IL-10⁺ Breg cells, while the epigenetic mechanism for the IL-10 expression remains largely unknown. It is well accepted that the histone acetylation/deacetylation is an important mechanism that regulates the expression of IL-10. We found that entinostat, an HDAC inhibitor, stimulated the induction of IL-10⁺ Breg cells by LPS in vitro and the formation of IL-10⁺ Breg cells to suppress CHS in vivo. We further demonstrated that entinostat inhibited HDAC1 from binding to the proximal region of the IL-10 expression promoter in splenic B cells, followed by an increase in the binding of NF-κB p65, eventually enhancing the expression of IL-10 in Breg cells.

• IMMUNE NETWORK
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• v.20 no.6
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• pp.50.1-50.11
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• 2020

Osteoporosis is prevalent in elderly women and it may cause dental implant failure. In particular, estrogen deficiency in postmenopausal women leads to higher rates of osteoporosis prevalence. Immune cell-mediated effects involving the development of osteoporosis have been studied previously; however, the role of IL-10-producing regulatory B (B10) cells in osteoporosis is largely unclear. Here, we examined the role of B10 cells in osteoporosis. C57BL/6 mice were subjected to ovariectomy (OVX). Fifteen weeks after OVX surgery, the first molar of the right maxillary was extracted, and twenty-four weeks after OVX surgery, serous progression of osteoporosis was observed in the alveolar bone. Moreover, the proportion of CD19⁺CD5⁺CD1d^high regulatory B cells, B10, and CD4⁺CD25⁺FoxP3⁺ regulatory T cells from the spleen of OVX mice decreased during the progression of osteoporosis, compared to controls. In contrast to regulatory cells, IL-17-producing Th (Th17) cell levels were increased in OVX mice. Adoptive transfer of B10 cells to OVX mice led to a decrease in Th17 cell abundance and inhibited the development of osteoporosis in the alveolar bone from OVX mice. Thus, our results suggest that B10 cells may help suppress osteoporosis development.