Sandler Anthony D, Chihara Hiroshi, Kobayashi Gen, Zhu Xiaoyan, Miller Michal A, Scott David L, Krieg Arthur M
Department of Surgery, University of Iowa College of Medicine, Iowa City, Iowa 52246, USA.
Cancer Res. 2003 Jan 15;63(2):394-9.
Granulocyte macrophage colony-stimulating factor (GM-CSF)-transduced autologous tumor cells form the basis of many immunotherapeutic strategies. We tested whether combining this approach with T-helper 1 (Th-1)-like immunostimulatory CpG oligodeoxynucleotides (CpG ODNs) would improve therapeutic efficacy in an established model of murine neuroblastoma. The weakly immunogenic Neuro-2a cell line was used in syngeneic A/J mice. CpG 1826 was tested for its antitumor effect alone and as an adjuvant to Neuro-2a cells retrovirally transduced to express murine GM-CSF (GM/Neuro-2a). Three days after wild-type (WT) tumor cell inoculation, mice in different groups were s.c. vaccinated in the opposite leg with combinations of WT neuro2a, irradiated (15 Gy) WT or GM/Neuro-2a transfectants with or without CpG 1826 (200 micro g). To test for the induction of memory responses, mice that rejected their tumor were rechallenged with WT Neuro-2a (1 x 10(6)) 7 weeks after vaccination. All of the mice in the control (unvaccinated) group died within 3 weeks after Neuro-2a inoculation. Most of the vaccinated groups had only minimal-to-modest antitumor responses, and the mice succumbed to tumor. Tumor growth was remarkably inhibited in the group of mice that received irradiated GM/Neuro-2a plus CpG and four (50%) of eight mice in this group survived tumor free. Tumor-free mice were resistant to further WT tumor cell challenge, indicating a memory response. Mechanistic studies showed that CpG alone induced a favorable Th-1-like cytokine immune response and vaccine-induced tumor cell killing was dependent on both CD4 and CD8 T cells that killed tumor cell targets by apoptosis. These results demonstrate that CpG ODNs enhanced the antitumor effect of irradiated GM-CSF secreting Neuro-2a cells. This vaccine strategy elicits a potent tumor antigen-specific immune response against established murine neuroblastoma and generates systemic neuroblastoma-specific immunity.
粒细胞巨噬细胞集落刺激因子（GM-CSF）转导的自体肿瘤细胞构成了许多免疫治疗策略的基础。我们测试了将这种方法与T辅助1（Th-1）样免疫刺激CpG寡脱氧核苷酸（CpG ODNs）相结合是否会提高已建立的小鼠神经母细胞瘤模型的治疗效果。在同基因A/J小鼠中使用免疫原性较弱的Neuro-2a细胞系。单独测试了CpG 1826的抗肿瘤作用，以及作为逆转录病毒转导以表达小鼠GM-CSF的Neuro-2a细胞（GM/Neuro-2a）的佐剂的作用。野生型（WT）肿瘤细胞接种三天后，不同组的小鼠在对侧腿部皮下接种WT neuro2a、经照射（15 Gy）的WT或GM/Neuro-2a转染细胞，加或不加CpG 1826（200μg）的组合疫苗。为了测试记忆反应的诱导情况，在接种疫苗7周后，用WT Neuro-2a（1×10⁶）对肿瘤已消退的小鼠进行再次攻击。对照组（未接种疫苗）的所有小鼠在接种Neuro-2a后3周内死亡。大多数接种疫苗的组只有轻微到中等程度的抗肿瘤反应，小鼠最终死于肿瘤。接受经照射的GM/Neuro-2a加CpG的小鼠组肿瘤生长受到显著抑制，该组8只小鼠中有4只（50%）无瘤存活。无瘤小鼠对进一步的WT肿瘤细胞攻击具有抗性，表明存在记忆反应。机制研究表明，单独的CpG可诱导良好的Th-1样细胞因子免疫反应，疫苗诱导的肿瘤细胞杀伤依赖于通过凋亡杀死肿瘤细胞靶标的CD4和CD8 T细胞。这些结果表明，CpG ODNs增强了经照射的分泌GM-CSF的Neuro-2a细胞的抗肿瘤作用。这种疫苗策略引发了针对已建立的小鼠神经母细胞瘤的强大肿瘤抗原特异性免疫反应，并产生了全身性神经母细胞瘤特异性免疫。
