Unmethylated CpG motif containing oligodeoxynucleotide(CpG ODN) can induce secretion of dendritic cells,and thus presents antigens efficiently,increases expression of costimulatory molecules,causes innate immunity response and adaptive immunity response,then plays anti-tumor roles.

Oligodeoxynucleotides containing CpG motifs have shown powerful immunoregulation effects, which are able to activate a variety of immune cells such as natural killer (NK) cells, monocytes,macrophages, dendritic cells(DC), B and T lymphocytes. CpG oligodeoxynucleotides (CpG ODN) can not only induce and enhance nonspecific and specific immune responses, but also regulate the type of immune responses through inducing Th1-type immune response and suppressing Th2-type immune response. DC are known to be the most powerful special antigen-presenting cells (APC) at present. It plays an important role in antigen recognition,antigen processing presenting, and T cell activation, and can kill various kinds of tumor cells. Recently, the immunotherapy based on tumor vaccines of dendritic cell has become more and more important. The research progress on dendritic cells for cancer treatment is reviewed in this article.

Objective To study the effects of CO2 pneumope ritoneum on the abdominal viscera metastasis and peritoneal implantation of gastric cancer cell line MKN45 during laparoscopic gastric surgery.Methods The gastric cancer cells metastatic model was eslhblished by injecting 1 ml(2×107/ml)human gastric cancer cell line MKN45 susDension into the caecum wall of 60 Balb/C mice.Two weeks later,the Balb/C mice were divided into CO2 pneumoperitoneum group(n=30)and laparotomy group(n=30). All mice were sacrificed 7 weeks later to investigate the abdominal viscera metastasis and peritoneal implantation of gastric cancer cells.Results Twenty-seven rats in CO2 pneumoperitoneum group were induced with tumor,including 8 with troear port implantation and 19 with organ metastasis;26 rats in laparotomy group were induced with tumor,including 7 with tracar port implantation and 19 with abdominal viscera metastasis,and the differences between the two groups had no statistical significance(x2=0.007,0.240,0.202,0.106,0.042,P＞0.05).Conclusions CO2 pneumoperitoneum does not stimulate the metastasis of gastric cancer(cells to peritoneum and abdominal viscera in Balb/C mice.Laparoscopic surgery for gastric cancer is safe and feasible.

Objective To explore the cultivated methods of dendritic cells (DC) and the killing effect of DC stimulated by CpG ODN1826 on gastritic cancer cells MKN45 in vitro. Methods DC was induced from peripheral blood monocytes stimulated by A group ( GM- CSF + IL-4 ), B group ( GM- CSF + IL-4 + TNF- α), C group(nonCpG ODN) and D group( CpG ODN 1826). The surface markers of DC was analyzed via flow cytometry, and the abilities to stimulate proliferation of allogenic lymphocyte by DC and antitumor experiment were detected by MTT assay. Results On day 10, a majority of cells showed typical morphology of DC in D group and B group with visible branching-like and pseudopod-like structures under microscope. The results of flow cytometry showed that there are significantly high expressed co-stimulated molecules such as CD40, CD1a,CD80, CD86 and MHC- Ⅱ in D group compared to other experimental groups ( P ＜ 0.05 ), which dramatically stimulate the proliferation of allogenic lymphocytes and enhance the killing activity of DC on gastric cancer cells. Conclusion This method can acquire relatively high purified DC, and CpG ODN can significantly induce the differentiation and maturation of DC isolated from peripheral blood and enhance the killing activity of DC on MKN45 by stimulating PBMC in vitro.