Tseng S H, Hwang L H, Lin S M
Department of Surgery, National Taiwan University Hospital, Taipei, R.O.C.
J Immunother. 1997 Sep;20(5):334-42. doi: 10.1097/00002371-199709000-00002.
To test whether cytokine gene therapy can be applied to an immunologically privileged site, such as the brain, we investigated antitumor immunity in the brain induced by cytokine-secreting glioma cells. Three cytokine genes, interleukin-2 (IL-2), interleukin-4 (IL-4), and granulocyte-macrophage colony-stimulating factor (GM-CSF) were transduced into a rat C6 glioma cell line via a retroviral vector, S2. Rats intracerebrally (IC) implanted with the C6 cells genetically engineered to secrete the cytokines, especially GM-CSF, manifested significantly higher survival rates than those with C6 cells or with C6 cells bearing the control vector (p < 0.002). In vivo, C6 tumors bearing the cytokine genes grew more slowly than wild-type tumors at any time point, and eventually diminished within 6 weeks after tumor cell implantation. Histopathological and immunohistochemical studies revealed that different cytokines induced diverse immune reactions. In the IL-2 group, CD4+ and CD8+ T cells dominated from day 3 to week 4, but disappeared at week 6. Some granulocytes were noted between weeks 2 and 4. In the IL-4 group, eosinophils were noted from day 3 to week 4, and CD4+ and CD8+ T cells, as well as macrophages at week 2. At week 6, only residual levels of macrophages and CD8+ T cells remained. In the GM-CSF group, granulocytes appeared as early as day 1 post-IC tumor implantation, and macrophages at day 2. CD4+ and CD8+ T cells were found from day 3 to week 4. At week 6, only residual CD4+ T cells and macrophages remained. Long-lasting antitumor immunity was confirmed in all groups by rechallenging surviving rats with wild-type C6 cells in the brain 100 days after implanting cytokine gene-bearing C6 cells. In vivo depletion of GM-CSF by anti-GM-CSF antibody further confirmed that the immune reaction induced by GM-CSF-secreting tumor cells were mainly from the action of GM-CSF, rather than the immunogenicity of C6 cells.
为了测试细胞因子基因疗法是否可应用于免疫赦免部位，如大脑，我们研究了分泌细胞因子的胶质瘤细胞在大脑中诱导的抗肿瘤免疫。通过逆转录病毒载体S2将三种细胞因子基因，即白细胞介素-2（IL-2）、白细胞介素-4（IL-4）和粒细胞-巨噬细胞集落刺激因子（GM-CSF）转导到大鼠C6胶质瘤细胞系中。脑内（IC）植入经基因工程改造以分泌细胞因子，尤其是GM-CSF的C6细胞的大鼠，其存活率显著高于植入C6细胞或携带对照载体的C6细胞的大鼠（p < 0.002）。在体内，携带细胞因子基因的C6肿瘤在任何时间点的生长都比野生型肿瘤缓慢，最终在肿瘤细胞植入后6周内缩小。组织病理学和免疫组织化学研究表明不同的细胞因子诱导了不同的免疫反应。在IL-2组中，CD4+和CD8+ T细胞在第3天至第4周占主导地位，但在第6周消失。在第2周和第4周之间观察到一些粒细胞。在IL-4组中，在第3天至第4周观察到嗜酸性粒细胞，在第2周观察到CD4+和CD8+ T细胞以及巨噬细胞。在第6周，仅残留少量巨噬细胞和CD8+ T细胞。在携带细胞因子基因的C6细胞植入100天后，通过用野生型C6细胞对存活大鼠进行脑内再次攻击，证实了所有组中都存在持久的抗肿瘤免疫。用抗GM-CSF抗体在体内消耗GM-CSF进一步证实分泌GM-CSF的肿瘤细胞诱导的免疫反应主要来自GM-CSF的作用，而不是C6细胞的免疫原性。
