Shim Jae Uoong, Rhee Joon Haeng, Jeong Ji Ung, Koh Young Il
Department of Internal Medicine, Chonnam National University Medical School & Hospital, Gwangju, Korea.
Clinical Vaccine R&D Center, Department of Microbiology, Chonnam National University Medical School, Gwangju, Korea.
Allergy Asthma Immunol Res. 2016 May;8(3):206-15. doi: 10.4168/aair.2016.8.3.206.
Invariant natural killer T (iNKT) cells play a critical role in the pathogenesis of asthma. We previously reported the association between circulating Th2-like iNKT cells and lung function in asthma patients and the suppressive effect of Toll-like receptor 5 ligand flagellin B (FlaB) on asthmatic in a mouse model. Thus, we investigated whether FlaB modulates the function of circulating iNKT cells in asthmatic patients.
Peripheral blood mononuclear cells (PBMCs) were treated with FlaB, and the secreted and intracellular cytokines of iNKT cells were evaluated by using ELISA and flow cytometry, respectively, following stimulation with α-galactosylceramide. Foxp3⁺ iNKT cells were also measured. To determine the effect of FlaB-treated dendritic cells (DCs) on iNKT cells, we co-cultured CD14⁺ monocyte-derived DCs and T cells from patients with house dust mite-sensitive asthma and analyzed intracellular cytokines in iNKT cells.
A reduction of IL-4 and IL-17 production by iNKT cells in PBMCs after FlaB treatment was alleviated following blocking of IL-10 signaling. A decrease in the frequencies of IL-4⁺ and IL-17⁺ iNKT cells by FlaB-treated DCs was reversed after blocking of IL-10 signaling. Simultaneously, an increase in Foxp3⁺ iNKT cells induced by FlaB treatment disappeared after blocking of IL-10.
FlaB may inhibit Th2- and Th17-like iNKT cells and induce Foxp3⁺ iNKT cells by DCs via an IL-10-dependent mechanism in asthmatic patients. In patients with a specific asthma phenotype associated with iNKT cells, FlaB may be an effective immunomodulator for iNKT cell-targeted immunotherapy.
不变自然杀伤T（iNKT）细胞在哮喘发病机制中起关键作用。我们之前报道了哮喘患者循环中Th2样iNKT细胞与肺功能之间的关联以及Toll样受体5配体鞭毛蛋白B（FlaB）在小鼠模型中对哮喘的抑制作用。因此，我们研究了FlaB是否调节哮喘患者循环中iNKT细胞的功能。
用FlaB处理外周血单个核细胞（PBMC），在用α-半乳糖神经酰胺刺激后，分别使用酶联免疫吸附测定（ELISA）和流式细胞术评估iNKT细胞分泌的细胞因子和细胞内细胞因子。还检测了Foxp3⁺ iNKT细胞。为了确定FlaB处理的树突状细胞（DC）对iNKT细胞的影响，我们将来自屋尘螨敏感哮喘患者的CD14⁺单核细胞衍生的DC与T细胞共培养，并分析iNKT细胞中的细胞内细胞因子。
在阻断IL-10信号后，FlaB处理后PBMC中iNKT细胞产生的IL-4和IL-17减少的情况得到缓解。在阻断IL-10信号后，FlaB处理的DC导致的IL-4⁺和IL-17⁺ iNKT细胞频率降低得到逆转。同时，在阻断IL-10后，FlaB处理诱导的Foxp3⁺ iNKT细胞增加消失。
在哮喘患者中，FlaB可能通过DC经由IL-10依赖性机制抑制Th2样和Th17样iNKT细胞并诱导Foxp3⁺ iNKT细胞。在具有与iNKT细胞相关的特定哮喘表型的患者中，FlaB可能是针对iNKT细胞的免疫治疗的有效免疫调节剂。
