Institute for Biophysics, Johannes Kepler University, Linz, Austria.
J Biol Chem. 2011 May 6;286(18):15973-9. doi: 10.1074/jbc.M110.192674. Epub 2011 Mar 15.
Invariant natural killer T (iNKT) cells are a population of T lymphocytes that play an important role in regulating immunity to infection and tumors by recognizing endogenous and exogenous CD1d-bound lipid molecules. Using soluble iNKT T cell receptor (TCR) molecules, we applied single molecule force spectroscopy for the investigation of the iNKT TCR affinity for human CD1d molecules loaded with glycolipids differing in the length of the phytosphingosine chain using either recombinant CD1d molecules or lipid-pulsed THP1 cells. In both settings, the dissociation of the iNKT TCR from human CD1d molecules loaded with the lipid containing the longer phytosphingosine chain required higher unbinding forces compared with the shorter phytosphingosine lipid. Our findings are discussed in the context of previous results obtained by surface plasmon resonance measurements. We present new insights into the energy landscape and the kinetic rate constants of the iNKT TCR/human CD1d-glycosphingolipid interaction and emphasize the unique potential of single molecule force spectroscopy on living cells.
不变自然杀伤 T(iNKT)细胞是一类 T 淋巴细胞，通过识别内源性和外源性 CD1d 结合的脂质分子，在调节感染和肿瘤的免疫中发挥重要作用。我们使用可溶性 iNKT T 细胞受体(TCR)分子，应用单分子力谱技术，研究了 iNKT TCR 对人 CD1d 分子与不同长度植物鞘氨醇链糖脂结合的亲和力，使用重组 CD1d 分子或脂类脉冲刺激的 THP1 细胞。在这两种情况下，与较短植物鞘氨醇脂质相比，含有较长植物鞘氨醇链的脂质负载的 iNKT TCR 与人 CD1d 分子的解离需要更高的非结合力。我们的研究结果结合以前通过表面等离子体共振测量获得的结果进行了讨论。我们对 iNKT TCR/人 CD1d-糖鞘脂相互作用的能量景观和动力学速率常数提出了新的见解，并强调了活细胞中单分子力谱技术的独特潜力。
