Iwashiro Michihiro, Jinyan Wang, Toda Masaaki, Linan Wang, Kato Takuma, Kuribayashi Kagemasa
Department of Oral and Maxillofacial Surgery, and Institute of Immunology, Faculty of Medicine, Kyoto University, Kyoto 606-8507, Japan.
Int Immunol. 2002 Dec;14(12):1459-68. doi: 10.1093/intimm/dxf107.
To attain one of the final goals for cancer immunotherapy, cytotoxic T lymphocyte (CTL) clones were selected on the basis of exogenous IL-2 independence after limiting dilution culture from mixed lymphocyte tumor cell culture cells of FBL-3 tumor-immune spleens. About 10% of the clones could be propagated up to >5 times by weekly passages in the presence of splenic feeder and stimulating tumor cells. Two of the representative FBL-3-specific CTL clones that were able to undergo the fifth passage were expanded in large numbers for adoptive transfer by two rounds of a weekly passage with medium containing IL-2. FBL-3-specific CTL clones thus obtained showed a strong ability to eliminate the established tumors when transferred into tumor-bearing nude mice. In addition, the cells were recovered from the mouse spleen even 8 months after the transfer. The most striking differences between the CTL clones used in this experiment and those maintained conventionally in the presence of IL-2 were the abilities to produce IL-2 by themselves and the high expression level of the integrin molecule, VLA-4, that disappeared when cultured completely in the continuous presence of IL-2 in vitro during 12 weeks. In addition, concomitant with the disappearance of exogenous IL-2 independence and VLA-4 expression, the CTL clones lost their capacity to eradicate the tumor in vivo. Thus, the higher capacity of CTL clones to produce IL-2 on their own seemed to be correlated with the in vivo efficacy for tumor eradication and the long-term maintenance of their physiological profiles typical of memory T cells.
为实现癌症免疫治疗的最终目标之一，从FBL - 3肿瘤免疫脾细胞的混合淋巴细胞肿瘤细胞培养物中，通过有限稀释培养，基于对外源性白细胞介素-2的非依赖性选择细胞毒性T淋巴细胞（CTL）克隆。在脾饲养细胞和刺激肿瘤细胞存在的情况下，约10%的克隆每周传代可扩增至5倍以上。两个能够传代至第五代的代表性FBL - 3特异性CTL克隆，通过在含白细胞介素-2的培养基中每周传代两轮进行大量扩增，用于过继转移。如此获得的FBL - 3特异性CTL克隆在转入荷瘤裸鼠时显示出强大的消除已建立肿瘤的能力。此外，即使在转移8个月后，细胞仍可从小鼠脾脏中回收。本实验中使用的CTL克隆与传统在白细胞介素-2存在下维持的克隆之间最显著的差异在于，它们自身产生白细胞介素-2的能力以及整合素分子VLA - 4的高表达水平，当在体外连续12周完全在白细胞介素-2存在下培养时，VLA - 4表达消失。此外，随着对外源性白细胞介素-2非依赖性和VLA - 4表达的消失，CTL克隆失去了在体内根除肿瘤的能力。因此，CTL克隆自身产生白细胞介素-2的能力更强似乎与体内根除肿瘤的疗效以及它们作为记忆T细胞典型生理特征的长期维持相关。
