Dendritic cells engineered to secrete anti-DcR3 antibody augment cytotoxic T lymphocyte response against pancreatic cancer in vitro

Figure 5 T cell responses induced by anti-DcR3 monoclonal antibody secreting dendritic cells. The T cells were co-cultured with RNA-dendritic cells (DCs) for 24 h. Then, the supernatants were collected, and the cytokine levels were measured by ELISA assay. A: ELISA test showed the cytokines of IL-12p70 and IFN-γ secreted by T cells pulsed by DC-tumor-anti-DcR3 RNA were higher than those secreted by T cells pulsed by DC-total tumor RNA without significant change of TNF-α. Meanwhile, IL-10 level was lower in DC-tumor-anti-DcR3 RNA than in DC-total tumor RNA (^aP < 0.05); B: CD4⁺ T cells and CD8⁺ T cells incubated with DCs encoding whole tumor antigens could produce extremely higher IFN-γ levels compared with those incubated with DCs as control or DCs treated with normal tissues (^aP < 0.01). Furthermore, the CD4⁺ T and CD8⁺ T cells incubated with DCs co-transfected total tumor RNA and anti-DcR3 mAb mRNA produced higher IFN-γ levels than those incubated with DC-total tumor RNA (^bP < 0.01); C: The CD4⁺ T and CD8⁺ T cells incubated with DCs loaded with whole tumor antigens showed a positive expression of IL-4, whereas a negative or weak expression of IL-4 was observed in DC-actin RNA and DC-PBMC RNA cells (^aP < 0.01). Moreover, decreased levels of IL-4 production were detected in CD4⁺ T cells stimulated by DCs co-transfected with total tumor RNA and anti-DcR3 mAb mRNA compared with DCs transfected with total tumor RNA individually (^bP < 0.01). The experiment was repeated three times representatively, and results are shown as mean ± SD. IL: Interleukin; ELISA: Enzyme-linked immunosorbent assay; PBMC: Peripheral blood monocyte cell; mAb: Monoclonal antibody.