Abstract:Objective:To construct of PSAspecific dendritic cell (DC) vaccine and to observe its in vitro antitumour activity, so as to pave a way for future study. Methods: Bone marrow precursors were isolated and bone marrow derived DCs were prepared. Mature DCs were pulsed by PSA, Lysate of cancer cells, OVA and PBS to yield PSADC, Lys DC, OvaDC, and NonDC, respectively. After primed by antigen, the changes of IL12 p70 and IL1β in the supernatant of dendritic cells were assessed by ELISA. The antigenspecific proliferation and cytotoxicity activity of T cellprimed by PSApulsed DCs were observed and the results were compared with those by Lys, Ova and PBSpulsed DCs. Results: Mature DCs were successfully derived from bone marrow cells with a purity higher than 95%. ELISA assay showed PSADC, LysDC and OvaDC group secreted high levels of IL12 p70 and IL1β than NonDC group (P<0.05). In addition, PSADCs and LysDCs had significantly stronger ability to stimulate the proliferation of CD4+T cells in 3day classic mixed lymphocyte reaction (MLR) compared with OvaDCs and NonDCs (P<0.01). Higher levels of IFNγ and IL2 were detected in PSADCs and LysDCs groups compared with the other two groups (P<0.01), whereas the levels of IL10 and IL4 were lower than the other two groups (P<0.05). Moreover, PSADCs and Lys DCs enhanced DTH responses of C57BL/6 mice after antigen immunization; the third antigen and control did not show the enhancement effect (P<0.05). To observe the in vitro antiPSA CTL reactions induced by PSADCs and LysDCs, the LNCaP cell line (PSA specific) was used as syngeneic target and the E.G7 cell line (H2b) was used as Ovaspecific target cells. Compared with OvaDCs and NonDCs, CTL cells induced by PSADCs, LysDCs had significantly enhanced antigenspecific CTL activity to LNCaP cells (P<0.05).Conclusion: DCbased PSAepitope vaccine can be prepared by pulsing DCs with PSA protein; the prepared vaccine has strong in vitro immune activity and can kill LNCaP cells.