Objective To explore the effects of anti-tumor immunity induced by dendritic cells (DCs) vaccine pulsed with PEP3-KLH (keyhole limpet hemocyanin) on induction of specific immunity against prostate cancers.Methods DCs were propagated from bone marrow of C57BL/6 mice in vitro with granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin-4 (IL-4).On day 5 of culture, DCs were harvested and incubated with PEP3-KLH or KLH.Then the DC vaccine was inoculated into C57BL/6 mice by subcutaneous injection for three times with an interval of two weeks.One week after the last vaccination, the levels of IL-2, IL-12, and interferon (IFN)-γwere measured with enzyme-linked immunosorbent assay (ELISA) kit.The aforementioned immunized mice with DC vaccines were challenged with transgenic adenocarcinoma of mouse prostate (TRAMP)-C2 tumor cells, the tumor growth curve was drawn, and survival rate was checked and compared.The cytotoxic T lymphocyte (CTL) activity induced by DCs was tested with lactate dehydrogenase (LDH) release method.The percentages of CD3 + , CD4+ ,or CD8 + T cells in tumor-infiltrating lymphocytes (TILs) were determined with flow cytometry.Results PEP3-KLH-DC group stimulated the body and induced higher levels of secreted IL-2, IL-12, and IFN-γ compared to DCs control and KLH-DC groups (P ＜ 0.01).The tumor of mice vaccinated with PEP3-KLHDC grew significantly slower than that injected with DCs or KLH-DC (P ＜0.01).Compared to the others, the survival rate in PEP3-KLH-DC group raised remarkably (P ＜ 0.01).PEP3-KLH-DC group induced more outstanding specific CTL activities of killing tumor cells than DCs control group and KLH-DC group (P ＜ 0.01), and the cytotoxicities of TILs in PEP3-KLH-DC group was significantly enhanced (P ＜0.01).The percentages of CD3 + , CD4 + , or CD8 + T cells in TILs (40.9％, 34.1％) in PEP3-KLH-DC group were significantly higher than those in DC-KLH (27.3％, 5.2％) or DCs (26.2％, 5.1％) group.Conclusions PEP3-KLH-DC vaccine can inhibit effectively tumor growth, enhance long-term survival in mice,intensify the local immunologic function of tumor, and elicit and promote profound specific anti-prostate cancer cellular immune responses.