Protective antitumor immunity induced by fixed tumor cells in combination with adjuvant in a murine hepatoma model

We previously reported that fixed tumor sections induced autologous cytotoxic T lymphocytes (CTL) from human peripheral blood lymphocytes in vitro. Here, we examined whether fixed tumor cells could stimulate in vivo immunity using a murine hepatoma model. Vaccination of syngeneic mice with fixed Hepa 1-6 cells in combination with OK-432 and tuberculin as an adjuvant resulted in a significant increase in survival of mice against live Hepa 1-6 cell challenge. In addition, the splenocytes from vaccinated mice secreted CD4+ T cell-mediated interferon-γ (IFN-γ) and exhibited a specific CTL response. These findings suggest that fixed tumor cells combined with an appropriate adjuvant induce effective antitumor immunity in vivo.