CpG增强DC疫苗对黑色素瘤B16-HLA-MAGE-3的免疫效果

Immune enhancement of CpG on DC vaccine for B16-HLA-MAGE-3 melanoma

目的:观察CpG对抗原肽负载DC疫苗免疫效果的增强作用。方法:分别用50μg/ml的MAGE-3271-279抗原肽、4μg/ml的CpG和MAGE-3271-279抗原肽(50μg/ml)+CpG(4μg/ml)刺激培养到第6天的小鼠骨髓DC细胞,2天后用LPS再刺激24小时诱导其成熟;给HLA-A*0201/Kb转基因鼠移植B16-HLA-MAGE-3黑色素瘤,并于小鼠荷瘤的第-4、5和8天分别于颈部皮下注射同系小鼠DC疫苗(2×105/鼠),观察荷瘤鼠肿瘤生长情况;在荷瘤的第23天处死小鼠,检测脾脏NK细胞活性。给正常HLA-A2转基因小鼠皮下注射DC疫苗,8周后接种肿瘤细胞,观察免疫记忆形成情况。结果:抗原肽负载的DC疫苗,在小鼠荷瘤的第14天之前,小鼠肿瘤生长受到抑制,在第15天后抑瘤作用不明显;CpG与MAGE-3271-279+CpG负载的DC疫苗可显著抑制荷瘤鼠肿瘤的生长,且可诱导较高的NK细胞活性。MAGE-3271-279+CpG负载的DC疫苗在免疫8周后依然可抑制肿瘤细胞的生长,说明可以诱导免疫记忆形成。结论:CpG对抗原肽负载的DC疫苗的免疫效果具有潜在的增强作用。

Objective：To observe the immune enhancing effects of CpG on peptide loaded DC vaccine, Methods： Mouse bone marrowderived DC was pulsed with 50μg/ml HLA-A＊0201-restricted peptide （MAGE-3271-279）,4μg/ml CpG or MAGE-3271-279（50μg/ml ） ＋ CpG （4μg/ml） on the day 6 of culture, respectively. After 24 hrs of stimulation pulsed or unpulsed DCs were fully activated with 100 ng/ml LPS for another 24 hrs.Then,the DC vaccines were injected into HLA-A2-transgenic mice on days -4,5 and 8 respectively of challenge with B16- HLA-MAGE-3 melanoma. The tumor volume was caculated everyday, and the splenic NK cytotoxicity was detected at the day 23 when the mice were sacrificed. Normal HLA-A-A2-transgenic mice were s. c. inoculated with the DC vaccine, and 8 weeks later challenged with the tumor cells to observe specific immune memory, Results： The peptide combined with CpG-treated DC vaccine was able not only to reduce the tumor growth significantly but also to induce specific immune memorry. Comparing with the PBS-DC, the tumor growth was inhibited, while NK activity of splenic lymphocytes was observed to be promoted to some extent in the group of CpG-pulsed DC vaccine.However,the tumor burden was shown to be reduced just at the begining of tumor challenge in the groups of the peptide-pulsed DC vaccine. Conclusion： CpG has potential immune enhancement effect on peptide-loaded DC vaccine.