Ueno Aruto, Arakawa Fumiko, Abe Hironori, Matsumoto Hisanobu, Kudo Toshio, Asano Ryutaro, Tsumoto Kohei, Kumagai Izumi, Kuroki Motomu, Kuroki Masahide
Department of Biochemistry, Fukuoka University School of Medicine, Japan.
Anticancer Res. 2002 Mar-Apr;22(2A):769-76.
The bacterial superantigen staphylococcal enterotoxin A (SEA) is an extremely potent activator of T lymphocytes when presented on major histocompatibility complex (MHC) class II molecules. To develop a tumor-specific superantigen for cancer therapy, we constructed a recombinant fusion protein of SEA and the single-chain variable fragment (scFv) of the FU-MK-1 antibody, which recognizes a glycoprotein antigen (termed MK-1 antigen) present on most carcinomas.
We employed recombinant DNA techniques to fuse recombinant mutant SEA to an scFv antibody derived from FU-MK-1 and the resulting fusion protein (SEA/FUscFv) was produced by a bacterial expression system, purified with a metal-affinity column, and characterized for its MK-1-binding specificity and its antitumor activity.
The SEA/FUscFv fusion protein retained the reactivity with MK-1-expressing tumor cells, introduced a specific cytotoxicity of lymphokine-activated killer T-cells to the tumor cells, and consequently suppressed the tumor growth in a SCID mouse xenograft model.
This genetically engineered SEA/FUscFv fusion protein may serve as a potentially useful immunotherapeutic reagent for human MK-1-expressing tumors.
细菌超抗原葡萄球菌肠毒素A（SEA）在主要组织相容性复合体（MHC）II类分子上呈递时是T淋巴细胞的极其有效的激活剂。为了开发用于癌症治疗的肿瘤特异性超抗原，我们构建了SEA与FU-MK-1抗体的单链可变片段（scFv）的重组融合蛋白，该抗体识别大多数癌上存在的一种糖蛋白抗原（称为MK-1抗原）。
我们采用重组DNA技术将重组突变SEA与源自FU-MK-1的scFv抗体融合，所得融合蛋白（SEA/FUscFv）由细菌表达系统产生，用金属亲和柱纯化，并对其MK-1结合特异性和抗肿瘤活性进行表征。
SEA/FUscFv融合蛋白保留了与表达MK-1的肿瘤细胞的反应性，使淋巴因子激活的杀伤性T细胞对肿瘤细胞产生特异性细胞毒性，从而在SCID小鼠异种移植模型中抑制了肿瘤生长。
这种基因工程SEA/FUscFv融合蛋白可能作为一种对表达人MK-1的肿瘤潜在有用的免疫治疗试剂。
