OBJECTIVETo study the antitumor effect GPI-CD80 fusion protein and its mechanisms.

METHODSA tumor vaccine was prepared by culturing HepG2 cells in the presence of purified GPI-CD80 followed by inactivation with mitomycin, with mitomycin-inactivated HepG2 cells as the control group. The two preparations were co-cultured with nude mouse splenic lymphocytes, and the changes of lymphocyte proliferation and the production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) were detected by MTT assay. The cytotoxic T-lymphocyte (CTL) activity was evaluated by LDH-release assay, and the changes of gross tumor volume were measured in tumor-bearing nude mice after administration of different vaccines.

RESULTSThe application of GPI-CD80 tumor vaccine resulted in significantly increased optical density, IL-2 and IFN-gamma levels and CTL activity of the nude mouse splenic lymphocytes in comparison with the control groups. The average tumor volume in nude mice treated with GPI-CD80 tumor vaccine was significantly smaller than that in negative control and blank control groups.

CONCLUSIONGPI-CD80 fusion protein may inhibit the tumor growth velocity in nude mice, possibly by promoting lymphocyte proliferation, stimulating the production of the cytokines IL-2 and IFN-gamma, and enhancing of CTL activity.