Dendritic Cells Induce The Specific Cytotoxic T Lymphocytes Against Prostate Cancer Tramp-C2 Cells Loaded With Freze-Thaw Antigen And PEP-3 Peptide

Objective:To investigate the immune responses of cytotoxic T lymphocytes (CTLs) against prostate cancer cells TRAMP-C2 after activated by dendritic cells (DCs) loaded with TRAMP-C2 freeze-thaw antigen and PEP-3 peptide in vitro. Materials and methods:Bone marrow-derived DCs from the bone marrow of the C57BL/6 were induced to mature by using the cytokine of rhGM-CSF and rhIL-4, and loaded with either the freeze-thaw antigen or PEP-3 peptide or both of them. The changes of the phenotypes of DCs were detected by flow cytometry. DCs and T-lymphocytes were co-cultured for 24h to induce the specific CTLs. The killing efficiency of the CTLs on TRAMP-C2 cells were detected by flow cytometry, CCK8, colony formation, transwell migration, and wound-healing assay. The levels of the IFN-γ、TNF-β and IL-12 secreted by DCs and CTL were measured by enzyme-linked immunosorbent assay (ELISA). Results:Compared with the unloaded DCs, the loaded DCs significantly increased the expression of several phenotypes related to DCs maturation (MHC-II, CDllc, CD40, CD80, CD86). CTLs, activated by DCs loaded with freeze-thaw antigen and PEP-3 peptide had more evident cytotoxicity against TRAMP-C2 cells in vitro. The cell apoptosis were increased while the ability of invasion and migration were lower than the other groups. The secretion levels of IFN-γ、TNF-β and IL-12, secreted by DCs loaded with antigen & PEP-3 and interaction with T cells, were more significantly than other groups. Conclusions:Our results suggest that the CTLs activated by DCs loaded with TRAMP-C2 freeze-thaw antigen and PEP-3 peptide had exerted a remarkable killing efficiency on TRAMP-C2 cells in vitro.