A fundamental research on DCs for their role in low dose chemotherapy.

Objective To investigate the value of dendritic cells in immunotherapy and their role in low dose chemotherapy(5-Fu,DDP).Method MFC was injected into 615 mice to get tumor models,and immature DCs were induced from bone marrow in vitro by rmGM-CSF and rmIL-4.All animals were divided into 4 groups: low dose chemotherapy group,DC group,low dose chemotherapy+DC group and control group.Apoptosis of tumor cells was detected by using LASB.The inhibition ratio of proliferation of MFCs,the proliferation of CTLs and its specific lethal effect on tumor cells were analysed.Result Low dose chemotherapy induced apoptosis of tumor cells.Inhibition ratio of proliferation of MFC of injected side were 100%,67.22%,57.98% respectively in both low dose chemotherapy and DC,low dose chemotherapy alone and DC alone.The inhibition ratio of proliferation of MFCs on injected side were 87.58%(low dose chemotherapy+DC group),59.69%(low dose chemotherapy group) and 48.24%(DC group) respectively.The DCs also increased proliferation and activation of CTLs,which reinforced the lethal effect on MFCs(P0.01).When the effector-to-target ratio was 40∶1,20∶1,10∶1 and 5∶1,the kill rate after 72 h averaged 87.64%,70.32%,34.63% and 13.87% respectively.Conclusion The mechanisms of low dose chemotherapy are correlated to apoptosis of tumor cells and immunologic enhancement.