Tsuboi Akihiro, Oka Yoshihiro, Udaka Keiko, Murakami Masaki, Masuda Tomoki, Nakano Akiko, Nakajima Hiroko, Yasukawa Masaki, Hiraki Akio, Oji Yusuke, Kawakami Manabu, Hosen Naoki, Fujioka Tatsuya, Wu Fei, Taniguchi Yuki, Nishida Sumiyuki, Asada Momotaro, Ogawa Hiroyasu, Kawase Ichiro, Sugiyama Haruo
Department of Molecular Medicine, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka, Suita City, Osaka 565-0871, Japan.
Cancer Immunol Immunother. 2002 Dec;51(11-12):614-20. doi: 10.1007/s00262-002-0328-9. Epub 2002 Oct 18.
The Wilms' tumor gene WT1 is overexpressed in most types of leukemias and various kinds of solid tumors, including lung and breast cancer, and participates in leukemogenesis and tumorigenesis. WT1 protein has been reported to be a promising tumor antigen in mouse and human. In the present study, a single amino-acid substitution, M-->Y, was introduced into the first anchor motif at position 2 of the natural immunogenic HLA-A2402-restricted 9-mer WT1 peptide (CMTWNQMNL; a.a. 235-243). This substitution increased the binding affinity of the 9-mer WT1 peptide to HLA-A2402 molecules from 1.82 x 10(-5) to 6.40 x 10(-7) M. As expected from the increased binding affinity, the modified 9-mer WT1 peptide (CYTWNQMNL) elicited WT1-specific cytotoxic T lymphocytes (CTL) more effectively than the natural 9-mer WT1 peptide from peripheral blood mononuclear cells (PBMC) of HLA-A2402-positive healthy volunteers. CTL induced by the modified 9-mer WT1 peptide killed the natural 9-mer WT1 peptide-pulsed CIR-A2402 cells, primary leukemia cells with endogenous WT1 expression and lung cancer cell lines in a WT1-specific HLA-A2402-restricted manner. These results showed that this modified 9-mer WT1 peptide was more immunogenic for the induction of WT1-specific CTL than the natural 9-mer WT1 peptide, and that CTL induced by the modified 9-mer WT1 peptide could effectively recognize and kill tumor cells with endogenous WT1 expression. Therefore, cancer immunotherapy using this modified 9-mer WT1 peptide should provide efficacious treatment for HLA-A2402-positive patients with leukemias and solid tumors.
威尔姆斯瘤基因WT1在大多数类型的白血病和各种实体瘤（包括肺癌和乳腺癌）中过表达，并参与白血病发生和肿瘤发生。据报道，WT1蛋白在小鼠和人类中是一种有前景的肿瘤抗原。在本研究中，在天然免疫原性的HLA - A2402限制性9聚体WT1肽（CMTWNQMNL；第235 - 243位氨基酸）的第2位的第一个锚定基序中引入了单个氨基酸取代M→Y。这种取代使9聚体WT1肽与HLA - A2402分子的结合亲和力从1.82×10⁻⁵ M增加到6.40×10⁻⁷ M。正如从增加的结合亲和力所预期的那样，修饰后的9聚体WT1肽（CYTWNQMNL）比来自HLA - A2402阳性健康志愿者外周血单个核细胞（PBMC）的天然9聚体WT1肽更有效地诱导WT1特异性细胞毒性T淋巴细胞（CTL）。由修饰后的9聚体WT1肽诱导的CTL以WT1特异性的HLA - A2402限制性方式杀死天然9聚体WT1肽脉冲的CIR - A2402细胞、具有内源性WT1表达的原发性白血病细胞和肺癌细胞系。这些结果表明，这种修饰后的9聚体WT1肽比天然9聚体WT1肽对诱导WT1特异性CTL更具免疫原性，并且由修饰后的9聚体WT1肽诱导的CTL可以有效识别和杀死具有内源性WT1表达的肿瘤细胞。因此，使用这种修饰后的9聚体WT1肽的癌症免疫疗法应为HLA - A2402阳性的白血病和实体瘤患者提供有效的治疗。
