[Dendritic cells present particulate E7 protein of human papillomavirus and induce strong immunity].

OBJECTIVE

To investigate the feasibility of using dendritic cell (DC)-beads-antigen (Ag) as novel cancer vaccine form with E7 as the target antigen.

METHODS

C57BL/6 mouse was killed and the femora were taken out. Marrow cells were isolated and cultured with IL-3 and granulocyte-macrophage growth stimulating factor (GM-CSF) so as to prepare DCs. Flow cytometry was conducted to analyze the phenotype. FITC-labeled polystyrene beads-ovalbumin (OVA) or polystyrene beads-human papillomavirus (HPV) E7 protein were added into the culture fluid to be co-cultured with the DCs for 3 hours. Flow cytometry was conducted to analyze the up-taking rates of polystyrene beads-OVA and of polystyrene beads-HPV E7 protein by the DCs and B3Z T cell hybridoma cells were co-cultured and then beads-OVA or beads-SIIFEKL polypeptide was added into the culture fluid. The absorbance was read. Twelve mice were injected with DC-beads-OVA, DC-beads-E7, DC-OVA antigen epitope (SIIFEKL), or DC-E7 epitope (RAHYNIVTF) into the plantae and killed in 36 hours to take out the iliac lymph nodes. Flow cytometry was conducted to analyze the phenotypes of the bead-positive cells. Mice were killed 10 days after immunization and their heart blood was collected. Enzyme linked immunosorbent assay was used to detect the levels of antibodies. Immunized and non-immunized mice were killed and their spleens were taken out. ELISPOT was used to detect the number of cells secreting interferon (IFN)gamma.

RESULTS

DCs were seen in the culture fluid of mice marrow cells 5 days after culture with IL-3 and GM-CSF. The bead-positive rates of bead-E7 and bead-OVA were 64% +/- 18% and 58% +/- 16% respectively (P > 0.05) in the IL-3DCs. The CD40 expression rate in the bead-positive cells in the graining iliac lymph nodes was significantly higher after feeding by beads-E7 in comparison with that before the feeding (P < 0.05), the NLDC145, and MHC-II expression rates were increased to a certain degree, however the F4/80 expression rate was decreased. The DCs fed with bead-OVA or with OVA antigen epitope SIIFEKL, especially the former, significantly activated the B3Z cells. The serum IgG level in the mice immunized by beads-E7 was significantly increases, the IgM level was increased slightly, however, the IgA level almost remained unchanged. The numbers of IFNgamma SFU in the splenic cells of the mice immunized by DC-bead-OVA and DC-bead-E7 were significantly higher than that in the unimmunized mice, especially those immunized by DC-bead-OVA.

CONCLUSION

DCs fed with beads-E7 can migrate to the draining lymph nodes and induce high level humeral and cellular immunity. DC-beads-Ag seems better than DC-epitope according to the strength of induced immunity. DC-beads-Ag may be an ideal vaccine form and can be used to develop other cancer vaccine.