Holzer U, Bethge W, Krull F, Ihle J, Handgretinger R, Reisfeld R A, Dohlsten M, Kalland T, Niethammer D, Dannecker G E
Children's University Hospital, Department of Oncology/Haematology, Tübingen, Germany.
Cancer Immunol Immunother. 1995 Aug;41(2):129-36. doi: 10.1007/BF01527409.
Superantigens such as the staphylococcal enterotoxin A (SEA) are among the most potent T cell activators known. They bind to major histocompatibility complex (MHC) class II molecules and interact with T cells depending on their T cell receptor (TCR) V beta expression. Superantigens also induce a variety of cytokines and trigger a direct cytotoxic effect against MHC-class-II-positive target cells. In order to extend superantigen-dependent cell-mediated cytotoxicity (SDCC) to MHC-class-II-negative neuroblastoma cells, SEA was linked to the anti-ganglioside GD2 human/mouse chimeric monoclonal antibody (mAb) ch14.18. Ganglioside GD2 is expressed on most tumours of neuroectodermal origin but is expressed to a lesser extent on normal tissues. The linkage of ch14.18 to SEA was achieved either with a protein-A-SEA fusion protein or by chemical coupling. Both constructs induced T-cell-mediated cytotoxicity towards GD2-positive neuroblastoma cells in an effector-to-target(E:T)-ratio- and dose-dependent manner in vitro. To reduce the MHC class II affinity of SEA, a point mutation was introduced in the SEA gene (SEAm9) that resulted in 1000-fold less T cell killing of MHC-class-II-expressing cells as compared to native SEA. However, a protein-A-SEAm9 fusion protein mediated cytotoxicity similar to that of protein-A-SEA on ch14.18-coated, MHC-class-II-negative neuroblastoma cells. Taken together, these findings suggest that superantigen-dependent and monoclonal-antibody-targeted lysis may be a potent novel approach for neuroblastoma therapy.
诸如葡萄球菌肠毒素A（SEA）之类的超抗原是已知最强效的T细胞激活剂之一。它们与主要组织相容性复合体（MHC）II类分子结合，并根据T细胞受体（TCR）Vβ的表达与T细胞相互作用。超抗原还可诱导多种细胞因子，并触发针对MHC-II类阳性靶细胞的直接细胞毒性作用。为了将超抗原依赖性细胞介导的细胞毒性（SDCC）扩展至MHC-II类阴性神经母细胞瘤细胞，将SEA与抗神经节苷脂GD2人/鼠嵌合单克隆抗体（mAb）ch14.18连接。神经节苷脂GD2在大多数神经外胚层起源的肿瘤上表达，但在正常组织上表达程度较低。ch14.18与SEA的连接可通过蛋白A-SEA融合蛋白或化学偶联实现。两种构建体在体外均以效应细胞与靶细胞（E:T）比例和剂量依赖性方式诱导对GD2阳性神经母细胞瘤细胞的T细胞介导的细胞毒性。为降低SEA对MHC II类的亲和力，在SEA基因中引入了一个点突变（SEAm9），与天然SEA相比，该突变导致对表达MHC-II类的细胞的T细胞杀伤减少1000倍。然而，蛋白A-SEAm9融合蛋白介导的细胞毒性与蛋白A-SEA对ch14.18包被的、MHC-II类阴性神经母细胞瘤细胞的细胞毒性相似。综上所述，这些发现表明超抗原依赖性和单克隆抗体靶向裂解可能是神经母细胞瘤治疗的一种有效的新方法。
