OBJECTIVETo explore the in vitro anti-tumor effect and mechanism of dendritic cell (DC) tumor vaccine induced by astragalus polysacharin (APS).

METHODSPeripheral blood mononuclear cells (PBMCs) isolated from human peripheral blood. DCs obtained from human peripheral blood were cultivated and added with culture solution for in vitro inducing them to immature DCs. On the 5th day of culture, 100 microg/mL (as the final concentration) APS was added to cells in the APS group. DCs were induced to mature in the cytokine groups by adding 20 ng/mL rhTNF-alpha (as the final concentration). Changes of morphology and phenotype of DCs were observed. Mature DCs were sensitized with tumor antigen SGC-7901 and co-cultured with allogeneic T cells. The proliferative function of T lymphocytes was detected by MTT assay. Levels of IL-12 and IFN-gamma in co-cultured supernatant were detected by ELISA. Cytotoxic lymphocytes (CTL) activated by DC were co-cultured with tumor cell SGC-7901. The specific killing capacity of CTL to target cells was detected by LDH release assay.

RESULTSThe morphological observation and phenotypic identification of APS induced DCs were in accordance with the characteristics of mature DCs. APS induced mature DCs could stimulate the proliferation of allogeneic T lymphocytes. The proliferation index of T cells increased with increased ratio of stimulator cells to effector cells (P < 0.05). Levels of IL-12 and IFN-gamma in co-culture supernatant significantly increased in a time-dependent manner (P < 0.05). CTL cells activated by sensitization of DCs could significantly kill tumor cells, and the killing effect increased along with increased effector-to-target ratio.

CONCLUSIONAPS could in vitro induce DCs to mature, promote its antigen-presenting capacity, effectively activate CTLs, and enhance anti-tumor function of the organism.