AB45. The study on specific umbilical blood DC vaccine for beige nude mice loaded human colorectal carcinoma to induce anti-tumor immunity

Background: With the using of tumor immunotherapy in the clinical treatment, a lot of problems were founded such as the factor of the tumor microenviroment, the suppressed anti-tumor immunocells and the poor long term treatment effect. We built the second load tumor model of SCID/beige nude mice to recur the tumor microenviroment in beginning of tumor development and recurrence. Specific umbilical blood Dc vaccines were used to stimulate the function of the immunocells and reduce the inhibition of tumor immune effector cells in tumor mincroenviroment.

Objective: The SCID/beige nude mice which second loaded human colon tumor cells, namely SW-1116 cells, were used to build the models. To observe the immunosuppression of specific umbilical blood Dc vaccine to tumor development of SCID/beige nude mice which were handled with human PBMCs.

Methods: Samples of peripheral blood in volunteers and umbilical blood in the childbirth pregnant women were collected to enrich Dcs by density gradient centrifugation. When the specific Dc vaccines matured they were gained, which hatched with human colon tumor SW-1116 cells. The male SCID/beige nude mice were used to build model, which subcutaneous injected with human SW-1116 cells in axillary of nude mice. The nude mice were observed to make sure that tumor were formed. The mice of the blank group was handled with nothing. That of the specific umbilical blood Dc vaccine group (ubDc), the specific peripheral blood Dc vaccine group (pbDc), and the naked peripheral blood Dc vaccine group (npbDc) were injected with human peripheral blood mononuclear cells to recur the humanized immune reconstruction. Twenty-four hours before injecting tumor cells, the mice of different groups were received the treatment with specific umbilical blood Dc vaccine, specific peripheral blood Dc vaccine and the naked peripheral blood Dc vaccine, respectively. The general life, tumor growing time, tumor size and weight of the mice were observed after they were given a suspension of human SW-1116 cells subcutaneously in contralateral axillary.

Results: The nude mice of blank group were found the bilateral tumor fast growth and burst, even part of them were poor and death. On the contrary, the nude mice protected by the immune prevention treatment were found the tumor slow growth, small tumor size and no burst or necrosis and death. Human umbilical cord blood Dc can load human SW-1116 antigen and matured as the antigen presenting cells. The tumor weights and volumes of the ubDc group were smaller than other groups. It is compared statistically significant.

Conclusions: The specific umbilical cord blood Dc vaccine can improve the immune function of peripheral immune cells and promote to improve their immune ability to kill tumor cells. They also have obvious inhibition on tumor cell growth and delay the tumor development. The specific umbilical cord blood Dc vaccine plays the key role in tumor immunotherapy.