Study On Anti-Gastric Carcinoma Efficacy Of P.acnes Mobilized DC Precursors In Vivo

OBJECTIVE: To study the in vivo antitumor efficacy of the Propionibacteriumacnes(P. acnes) mobilized F4/80~B220~CDllc+ cells matured by treatment with granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin 4 (IL-4), and then pulsed with mouse forestomah cancer ( MFC ) cells lysate in vitro.METHODS: P.acnes mobilized F4/80"B220"CDllc+DC precursors werematured in vitro , loaded with MFC cells lysate to create vaccine; create established MFC model with 615 mouse, and then inject vaccine subcutaneously, to evaluate the treatment and long-term antitumor efficacy of DC vaccine by analyzing the tumor size and the survival of mice ; 615 mice were injected subcutaneously with DC vaccine and then were challenged with MFC cells, also evaluate the prevention efficacy of DC vaccine by analyzing the tumor size and the survival of mice. By analyzing T cells CTL ability and secretion of IFN from survived tumor free mice in vitro, to evaluate whether the DC vaccine induced antitumor ability is MFC -specific.RESULTS: 24 days after the P.acnes mobilized DC vaccine was injectedsubcutaneously into the established MFC loading mice, the mean size of the tumor of the P.acnes-DC-Ag group is 9.60?0.41mm, the tumor of 3 mice obliterated(compared with control groups, P<0.01 ) ; those 3 mice were rechallenged at days 60 with MFC cells, and still remained tumor free until 90d when we stopped observation,while all mice in 3 control groups died within 28 days after MFC cells inoculation, the difference between experimental and control groups is statistically significam%P<0.01); P.acnes mobilized DC vaccine immunized mice received the firt challenge of MFC cells by subcutaneous injection. 24 days after the challenge, the mean diameter is 3.64?.87mm(compared withcontrol groups, P<0.01),after receiving the second MFC cells challenge, 50%mice were still alive and remained tumor free 60 days after the first tumor challenge,(all mice in control groups died within 30 days after the first MFC cells challenge), (P<0.01);The splenic T cells from survived tumor free mice in the experimental groups showed specific cytotoxic activity against MFC cells ex vivo.CONCLUSIONS: 1. Peripheral blood F4/80"B220~CDllc+ cells mobilized byP. acnes are DC precursors, can differentiate to immunogenic DC cultured with GM-CSF and IL-4 in vitro; 2. DC vaccine that loading MFC cells antigen has specific killing effect and long-term anti-tumor effect on MFC cells :; 3. That DC vaccine has a long-term and specific protective immune effect on mice;...