Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
Eur J Immunol. 2019 Mar;49(3):443-453. doi: 10.1002/eji.201847647. Epub 2018 Dec 3.
Natural killer T (NKT) cells recognize glycolipids presented on CD1d. They share features of adaptive T lymphocytes and innate NK cells, and mediate immunoregulatory functions via rapid production of cytokines. Invariant (iNKT) and diverse (dNKT) NKT cell subsets are defined by their TCR. The immunological role of dNKT cells, that do not express the invariant TCRα-chain used by iNKT cells, is less well explored than that of iNKT cells. Here, we investigated signals driving Toll-like receptor (TLR) ligand activation of TCR-transgenic murine dNKT cells. IFN-γ production by dNKT cells required dendritic cells (DC), cell-to-cell contact and presence of TLR ligands. TLR-stimulated DC activated dNKT cells to secrete IFN-γ in a CD1d-, CD80/86- and type I IFN-independent manner. In contrast, a requirement for IL-12p40, and a TLR ligand-selective dependence on IL-18 or IL-15 was observed. TLR ligand/DC stimulation provoked early secretion of pro-inflammatory cytokines by both CD62L and CD62L dNKT cells. However, proliferation was limited. In contrast, TCR/co-receptor-mediated activation resulted in proliferation and delayed production of a broader cytokine spectrum preferentially in CD62L dNKT cells. Thus, innate (TLR ligand/DC) and adaptive (TCR/co-receptor) stimulation of dNKT cells resulted in distinct cellular responses that may contribute differently to the formation of immune memory.
自然杀伤 T (NKT) 细胞识别 CD1d 呈递的糖脂。它们具有适应性 T 淋巴细胞和先天 NK 细胞的特征,并通过快速产生细胞因子来介导免疫调节功能。不变 (iNKT) 和多样 (dNKT) NKT 细胞亚群是由其 TCR 定义的。与 iNKT 细胞不同,不表达 iNKT 细胞使用的不变 TCRα 链的 dNKT 细胞的免疫学作用尚未得到充分探索。在这里,我们研究了驱动 Toll 样受体 (TLR) 配体激活 TCR 转基因鼠 dNKT 细胞的信号。dNKT 细胞 IFN-γ 的产生需要树突状细胞 (DC)、细胞间接触和 TLR 配体的存在。TLR 刺激的 DC 以 CD1d-、CD80/86-和 I 型 IFN 非依赖性方式激活 dNKT 细胞分泌 IFN-γ。相比之下,观察到需要 IL-12p40,并且 TLR 配体选择性地依赖于 IL-18 或 IL-15。TLR 配体/DC 刺激引发 CD62L 和 CD62L dNKT 细胞早期分泌促炎细胞因子。然而,增殖受到限制。相比之下,TCR/共受体介导的激活导致增殖和延迟产生更广泛的细胞因子谱,主要在 CD62L dNKT 细胞中。因此,dNKT 细胞的先天 (TLR 配体/DC) 和适应性 (TCR/共受体) 刺激导致不同的细胞反应,可能对免疫记忆的形成有不同的贡献。