Shimamura Michio, Huang Yi-Ying, Okamoto Naoki, Watanabe Yutaka, Murakami Yoshiko, Kinoshita Taroh, Hirabayashi Yoshio, Murakata Chikara, Ito Yukishige, Ogawa Tomoya
Developmental Immunology Unit, Mitsubishi Kagaku Institute of Life Sciences, 11 Minamiooya, Machida, Tokyo 194-8511, Japan.
FEBS J. 2007 Jun;274(11):2921-32. doi: 10.1111/j.1742-4658.2007.05826.x. Epub 2007 May 4.
We have previously demonstrated that alpha-mannosyl ceramide and its derivatives promote immune responses of NK1.1(+) invariant Valpha19-Jalpha33 T cell receptor (TCR) alpha(+) T cells (Valpha19 NKT cells). In this study, attempts were made to determine the structural requirements for natural ligands for Valpha19 NKT cells. Naturally occurring and synthetic glycolipids were analyzed for their ability to stimulate the cells prepared from invariant Valpha19-Jalpha33 TCR transgenic mice, in which development of Valpha19 NKT cells is facilitated. As a result, alpha-mannosyl phosphatidylinositols such as 2,6-di-alpha-mannosyl phosphatidylinositol and alpha-mannosyl-4alpha-glucosaminyl-6-phosphatidylinositol (alpha-Man-GlcNH(2)-PtdIns) as well as alpha-mannosyl ceramide derivatives were found to activate the cells from the transgenic mouse liver, gut lamina propria and spleen in vivo and in vitro. Thus, glycolipids with nonreducing end alpha-mannosyl residues are suggested to be potent antigens for Valpha19 NKT cells. Next, a series of invariant Valpha19-Jalpha33 TCR(+) hybridomas, each with variations in the sequence of the Valpha-Jalpha junction and the TCR beta chain, were tested for responsiveness toward the alpha-mannosyl glycolipids. A loose correlation between the primary structure of the TCR and the reactive glycolipids was observed. For instance, hybridomas expressing TCRs consisting of an alpha chain with a variation in the Valpha19-Jalpha33 junction and a Vbeta6(+)beta chain showed affinity towards alpha-mannosyl ceramide and alpha-Man-GlcNH(2)-PtdIns, whereas those expressing TCRs with an invariant Valpha19-Jalpha33 alpha chain and a Vbeta8(+)beta chain responded to 2,6-di-alpha-mannosyl phosphatidylinositol. Thus, it is suggested that Valpha19 NKT cells with microheterogeneity in the TCR structure have been generated for defense against various antigens expressing alpha-mannosyl glycolipids.
我们之前已经证明，α-甘露糖基神经酰胺及其衍生物可促进NK1.1(+)恒定Valpha19-Jalpha33 T细胞受体（TCR）α(+) T细胞（Valpha19 NKT细胞）的免疫反应。在本研究中，我们试图确定Valpha19 NKT细胞天然配体的结构要求。分析了天然存在的和合成的糖脂刺激从恒定Valpha19-Jalpha33 TCR转基因小鼠制备的细胞的能力，在这种小鼠中Valpha19 NKT细胞的发育得到促进。结果，发现诸如2,6-二-α-甘露糖基磷脂酰肌醇和α-甘露糖基-4α-葡糖胺基-6-磷脂酰肌醇（α-Man-GlcNH(2)-PtdIns）等α-甘露糖基磷脂酰肌醇以及α-甘露糖基神经酰胺衍生物在体内和体外均可激活转基因小鼠肝脏、肠道固有层和脾脏中的细胞。因此，具有非还原端α-甘露糖基残基的糖脂被认为是Valpha19 NKT细胞的有效抗原。接下来，测试了一系列恒定Valpha19-Jalpha33 TCR(+)杂交瘤，每个杂交瘤在Valpha-Jalpha连接序列和TCRβ链上都有变化，以检测它们对α-甘露糖基糖脂的反应性。观察到TCR一级结构与反应性糖脂之间存在松散的相关性。例如，表达由Valpha19-Jalpha33连接有变化的α链和Vbeta6(+)β链组成的TCR的杂交瘤对α-甘露糖基神经酰胺和α-Man-GlcNH(2)-PtdIns有亲和力，而表达具有恒定Valpha19-Jalpha33α链和Vbeta8(+)β链的TCR的杂交瘤对2,6-二-α-甘露糖基磷脂酰肌醇有反应。因此，有人提出，TCR结构具有微异质性的Valpha19 NKT细胞是为了抵御表达α-甘露糖基糖脂的各种抗原而产生的。
