Abstract: Objective Our former mice model research showed that after CIK cells were co-cultured with Dendritic cells (DC) loaded with multidrug resistance tumor antigen, the tumor were inhibited most on the same tumor bearing mice model. So we further research into the anti-tumor effect on tumor bearing mice model. Methods DC and CIK were respectively cultured from peripheral blood mononuclear cells (PBMC) derived from healthy individuals. MCF-7/ADR, a kind of breast cancer cell line expressed multidrug resistance, was prepared to obtain the antigen lyses. CIK was co-cultured with DC pulsed or unpulsed by the above antigen lyses (AP-DC+CIK and DC+CIK). So there were AP-DC+CIK, DC+CIK and CIK groups, NS was used as control group. The tumor-bearing mice were injected by intravenous with the above 4 groups’ effector cells. This study researched on the expression of MDR1, the apoptosis of tumor cells and the expression of Bcl-2 and Bax associated with apoptosis. Results After CIK co-cultured with DC, the anti-tumor effect of CIK cells were increased. The AP-DC+CIK group had the highest apoptosis index, and the lowest MDR1 expression. In above 4 groups, the AP-DC+CIK group had the highest Bax and lowest Bcl-2 expression. But the NS group was on the contrary, which meaned the lowest Bax and highest Bcl-2 expression. The difference between each two groups was significance. Conclusion After CIK cells were co-cultured with DC loaded with multidrug resistance tumor antigen, the quantity of CD4+T was increased obviously, which could induce the tumor cells apoptosis through activating Fas/FasL apoptosis pathway.

Key words: CIK, DC, Bax, Bcl-2, Fas/FasL