Wang Keng, Tao Lei, Su Jianbing, Zhang Yueyang, Zou Binhua, Wang Yiyuan, Zou Min, Chen Nana, Lei Linsheng, Li Xiaojuan
Laboratory of Anti-inflammatory Immunomodulatory Pharmacology, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, PR China; Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, PR China; Department of Clinical Pharmacy, The Affiliated Nanhai Hospital of Southern Medical University, Foshan 528200, PR China.
Laboratory of Anti-inflammatory Immunomodulatory Pharmacology, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, PR China; Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, PR China.
Mol Immunol. 2017 Jul;87:188-199. doi: 10.1016/j.molimm.2017.04.016. Epub 2017 May 12.
Certain B cells termed as "regulatory B cells" (Bregs) can suppress the ongoing immune responses and a splenic CD5CD1d Breg subset identified earlier was shown to exert its regulatory functions through secretion of IL-10. Though FasL expression is an alternative mechanism of immune suppression used by B cells, little is known about the FasL expressing CD5CD1d Bregs. In this study, we isolated splenocytes or splenic CD19 B cells and compared the efficiency of toll-like receptor(TLR)4 ligand (lipopolysaccharide) with TLR9 ligand (CpG), anti-CD40 and TLR9 ligand (CpG) plus anti-CD40 on the FasL expression of splenic CD5CD1d Bregs by flow cytometry. FasL expression in CD5CD1d B cells was rapidly increased after TLR4 ligation. Intriguingly, anti-CD40 and CpG plus anti-CD40 combinations failed to stimulate FasL expression in CD5CD1d B cells although the IL-10 production was up-regulated in this subset. In addition, LPS and other B10-cell inducers increased the expression of surface molecules like CD86 and CD25, which are correlated to the regulatory functions of B cells. Furthermore, NF-κB and NF-AT inhibitors decreased the TLR4-activated FasL expression in CD5CD1d B cells. Then we sorted splenic CD5CD1d Bregs using flow cytometry and found that TLR4-activated CD5CD1d Bregs suppressed the proliferation of CFSE-labeled CD4 T cells in vitro, which was partly blocked by anti-FasL antibody. In oxazolone-sensitized mice having contact hypersensitivity, FasL expression in splenic CD5CD1d B cells was decreased compared to the control group after TLR4 ligation. Our findings suggest that the regulatory function of CD5CD1d B cells could be partly mediated by Fas-FasL pathway and this FasL expressing CD5CD1d Bregs might participate in the regulation of inflammatory diseases.
某些被称为“调节性B细胞”（Bregs）的B细胞能够抑制正在进行的免疫反应，先前鉴定出的脾脏CD5⁺CD1d⁺ Breg亚群被证明通过分泌白细胞介素-10发挥其调节功能。尽管FasL表达是B细胞用于免疫抑制的另一种机制，但对于表达FasL的CD5⁺CD1d⁺ Bregs知之甚少。在本研究中，我们分离了脾细胞或脾脏CD19⁺ B细胞，并通过流式细胞术比较了Toll样受体（TLR）4配体（脂多糖）与TLR9配体（CpG）、抗CD40以及TLR9配体（CpG）加抗CD40对脾脏CD5⁺CD1d⁺ Bregs的FasL表达的影响。TLR4连接后，CD5⁺CD1d⁺ B细胞中的FasL表达迅速增加。有趣的是，抗CD40和CpG加抗CD40的组合未能刺激CD5⁺CD1d⁺ B细胞中的FasL表达，尽管该亚群中的白细胞介素-10产生上调。此外，脂多糖和其他B10细胞诱导剂增加了如CD86和CD25等表面分子的表达，这些分子与B细胞的调节功能相关。此外，NF-κB和NF-AT抑制剂降低了CD5⁺CD1d⁺ B细胞中TLR4激活的FasL表达。然后我们使用流式细胞术分选脾脏CD5⁺CD1d⁺ Bregs，发现TLR4激活的CD5⁺CD1d⁺ Bregs在体外抑制了CFSE标记的CD4⁺ T细胞的增殖，这部分被抗FasL抗体阻断。在患有接触性超敏反应的恶唑酮致敏小鼠中，与对照组相比，TLR4连接后脾脏CD5⁺CD1d⁺ B细胞中的FasL表达降低。我们的研究结果表明，CD5⁺CD1d⁺ B细胞的调节功能可能部分由Fas-FasL途径介导，并且这种表达FasL的CD5⁺CD1d⁺ Bregs可能参与炎症性疾病的调节。
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