三种细菌DNA及CpG寡核苷酸抗肿瘤免疫的比较实验研究

Comparison of Antitumor Immunity with Three Kinds of Bacterial DNA and CpG Oligodeoxynucleotide

用大肠埃希菌、铜绿假单胞菌和双歧杆菌的DNA与CpG寡聚核苷酸 (CpGoligodeoxynucleotides ,CpGODN)对荷瘤鼠进行治疗 ,比较 3种细菌DNA及CpGODN的抗肿瘤免疫作用 ,以筛选最好的细菌DNA及CpG序列用于肿瘤治疗。分别提取 3种细菌DNA并合成 2条CpGODN序列 ,在肝癌HcaFA3细胞株荷瘤小鼠模型上进行免疫治疗 ,以存活期、抑瘤率、NK/Mφ细胞活性及细胞因子 (IFN γ、TNF α、IL 2、IL 12等 )分泌活性等为指标 ,比较 3种细菌DNA之间及CpGODN的抗肿瘤免疫效果。 3种细菌DNA均能使荷瘤鼠的存活期延长 1倍以上 ,但三者之间无显著性差异 (P >0 .0 5 )。抑瘤率为 6 4 .0 3%～ 79.5 0 % (P <0 .0 1) ,而CpGODN的抑瘤率为 4 5 %～ 5 1%之间 (P <0 .0 5 ) ,3种细菌DNA以及CpGODN均能显著增强NK细胞和Mφ细胞的杀伤活性 (P <0 .0 5 ) ,但细菌DNA在诱导细胞因子 (IL 2、IFN、TNF等 )以及下调肿瘤细胞端粒酶活性方面 ,CpGODN作用强于细菌DNA。

Antitumor immunity of DNA and CpG oligodeoxynucleotide (CpG ODN) from three bacteria, E.coli, Pseudomonas aeruginosa, and Bifidobacterium longum, was compared by using them to treat tumor-bearing mice to screen the best DNA and CpG ODN sequence for antitumor immunotherapy. DNA from three bacteria was extracted respectively to synthesise two CpG ODN sequences to carry out immunotherapy on liver cancer HcaFA3 cell strain tumor-bearing mice model. Survival time, tumor-inhibition rate, NK/MФ cell activity, and the secretion activity of cell factors (IFN-γ,TNF-α,IL-2,IL-12 etc.) were used as indexes to compare the antitumor immunotherapy effects among the three DNA and CpG ODN. The results showed that all three bacterial DNA could prolong the survival time of the tumor-bearing mice by over one time, but no significant discrepancy existed among them \{(P>0.05)\}. The tumor inhibition rate (TIR) of three DNA was 64.03%～79.50% (P<0.01), and the TIR of CpG ODN was 45%～51% (P<0.05). The three DNA and CpG ODN could significantly increase the killing activity of NK and MФ cells, however, CpG ODN was stronger than bacterial DNA on inducing the cell factors (IL-2, IFN, TFN etc.) as well as on inducing telomerase activity of tumor cell on down-regulation.