Antitumor activities of human dendritic cells derived from peripheral and cord blood

To observe the biological specialization of human peripheral blood dendritic cells (DC) and cord blood derived DC and its effects on effector cells killing human hepatocarcinoma cell line BEL-7402. in vitro.

The DC biological characteristics were detected with immunohistochemical and MTT assay. Two antitumor experiment groups are divided: peripheral blood DC and cord blood DC groups. Peripheral blood DC groups used LAK cells as the effector cells and BEL-7402 as target cells, while cord blood DC groups used CTL induced by tumor antigen twice pulsed DC as effector cells and BEL-7402 as target cells, additional peripheral blood DC and cord blood DC are added to observe its stimulating activities to effector cells. The effector's cytotoxicity to tumor cells were detected with neutral red colorimetric assay at two effector/target ratios of 5:1 and 10:1.

Peripheral blood DC and cord blood DC highly expressed HLA-ABC, HLA-DR, HLA-DQ, CD54 and S-100 protein. The stimulating activities to lymphocyte proliferation were compared between experimental groups (DC added) and control group (no DC added), in six experiment subgroups,the DC/lymphocyte ratio was sequentially 0.25:100, 0.5:100, 1:100, 2:100, 4:100 and 8:100.A values were sequentially 0.75396+/-0.009, 0.84916+/-0.010, 0.90894+/-0.012, 0.98371+/-0.007, 1.01299+/-0.006 and 1.20384+/-0.006 in peripheral blood DC groups and 0.77650+/-0.005, 0.83008+/-0.007, 0.92725+/-0.007, 1.05990+/-0.010, 1.15583+/-0.011, 1.22983+/-0.011 in cord blood DC groups. A value was 0.59517+/-0.005 in control group. The stimulating activities were higher in experimental groups than in control group (P<0.01), which were increased when the DC concentration was enlarged (P<0.01). Two differently derived DCs had the same phenotypes and similar stimulating activities (P<0.05). In peripheral blood DC groups, the cytotoxicity of the LD groups (experimental groups) and L groups (control group) was 58.16%+/-2.03% (5:1), 46.18%+/-2.25% (10:1) and 38.13%+/-1.29% (5:1) and 65.40%+/-1.56% (10:1) respectively; in cord blood DC groups, TD groups (experimental groups) and T groups (control groups) were 69.71%+/-2.33 % (5:1), 77.64%+/-1.94% (10:1) and 56.89%+/-1.82% (5:1) and 60.99%+/-1.42% (10:1) respectively.The cytotoxicity activities were enhanced with increased effector/target ratio (P<0.01). At the same effector/target ratio, the cytotoxicity of experimental groups were bigger than that of control groups (P<0.01). The cytotoxicity activities of cord blood DC groups were higher than that of peripheral blood DC groups (P<0.01).

Peripheral blood DC and cord blood DC are mature DC in morphology and function, both can enhance the effector cell killing activities to hepatocarcinoma cells. DC pulsed with tumor antigen can induce higher specific CTL activity than unpulsed DC.